ECON 2302 Example SR Firm Graphs/Graphing solutions (Unit 2)

Summary

In this video, Professor Hank Lewis guides students through an analysis of how to solve short-run firm graphs as part of Unit 2 in his microeconomics course. Specifically addressing those who missed class, the video focuses on the methodology for solving graph problems, examining market structures, and determining whether businesses should operate or shut down in the short run based on economic principles. Professor Lewis uses a step-by-step approach and tackles several examples to ensure comprehension, highlighting key economic concepts such as monopolistic competition and perfect competition, while offering insights into long-run considerations.

Highlights

• Professor Lewis addresses absences by revisiting graph solutions 📈
• Clear explanations on monopolistic vs perfect competition market structures 🤔
• Dive into the graph intricacies to determine firm operation strategies 🔍
• Compare demand to average variable and total costs for shutdown/profit analysis 📉
• A glimpse into the long-run implications of short-run business decisions 🚀

Key Takeaways

• Understanding demand curves is crucial for analyzing market structure 🎯
• Learn how to decide if a firm should produce or shut down in the short run 👩‍🏫
• Monopolistic and perfect competitions have distinct characteristics and behaviors 📊
• Economic profits and losses can be deciphered through careful graph analysis 💹
• Long-run decisions are informed by short-run operations and potential exits 🔄

Overview

Professor Lewis starts by explaining the importance of understanding demand curves to classify market structures. He stresses how the slope of these curves can indicate whether a firm is in a monopolistic competition or perfect competition scenario. A shallow negative slope suggests monopolistic competition, while a horizontal demand curve indicates perfect competition, as addressed in the video.

The professor systematically explains the criteria for deciding whether a business should continue operations or shut down in the short run. By comparing the price with average variable costs, students learn to apply these principles in determining the viability of continued production. Through examples, students get a clear picture of when economic losses or profits occur, depending on the intersection of critical cost curves.

Concluding the session, Lewis discusses long-run scenarios, underlining the significance of initial short-run decisions, which may lead to market exit or continued production. He encourages students to apply these concepts to their practice problems, promising a firm understanding as long as they grasp these foundational ideas.

Chapters

• 00:00 - 00:30: Introduction and Overview Professor Lewis provides an overview of the session targeted at microeconomics students. The session aims to assist students who missed the class on solving short-run graphs for various businesses. Professor Lewis mentions that the focus will be on solving the first three short-run graphs from the practice problem set. The session involves sharing the screen to facilitate the demonstration.
• 00:30 - 01:00: Graph Solving Process This chapter focuses on the step-by-step process of solving graphs. The main idea is to analyze graphs by examining the demand curve to determine under which market structure a firm is operating. The steepness or flatness of the demand curve plays a crucial role in this analysis, linking back to a previous discussion and a test problem from unit 1. The chapter begins with an emphasis on understanding these elements to answer key economic questions related to market structure.
• 01:00 - 03:00: Market Structures and Demand Curve This chapter discusses different market structures and their respective demand curves, such as monopoly, perfect competition, and monopolistic competition. It explains that a monopoly has a steep negative slope in its demand curve, whereas perfect competition features a horizontal demand curve. The primary discussion focuses on monopolistic competition, where the demand curve has a shallow negative slope. The chapter encourages the use of explanations, potentially employing abbreviations like 'b/c' for 'because' to facilitate understanding.
• 03:00 - 05:30: Short Run Production Decisions The chapter discusses short-run production decisions for businesses, specifically focusing on the short-run shutdown rule. According to this rule, a firm should compare the market price (P star) to the minimum average variable cost. If the market price is strictly less than the minimum average variable cost, then the firm should shut down its operations in the short run. However, if the price is greater than or equal to the minimum average variable cost, the firm should continue producing. The demand curve is emphasized as the source for reading these prices.
• 05:30 - 10:00: Economic Loss and Shutdown Decision This chapter discusses the economic considerations involved in deciding whether to continue production or to shut down. It highlights the importance of comparing the price to the average variable cost (AVC) curve. If the price is greater than the minimum AVC, it is better to produce; however, if the demand curve is consistently below the AVC, it is more cost-effective to shut down production.
• 10:00 - 11:00: Long Run Market Exit In the chapter 'Long Run Market Exit,' the discussion focuses on the economic principles that dictate whether a firm should continue operating or shut down in the long run. It elaborates on the relationship between the demand curve, represented simply as 'D', and the average variable costs (AVC). If the demand curve consistently remains below the average variable cost for all production quantities, it becomes economically viable for the firm to cease operations. Part C of the discussion delves into what outcomes firms can expect in terms of profit or loss when they decide to shut down. The chapter uses graphical analysis and hypothetical table problems to illustrate these concepts to the readers or listeners.
• 11:00 - 16:00: Graph G2 Analysis The chapter discusses the economic scenario when a firm produces no output but incurs costs. It highlights that with zero output, the firm's total revenue is zero, but it still faces the burden of fixed costs, leading to an economic loss. The analysis points out the immediate financial impact when a firm shuts down, emphasizing the unavoidable expenses that persist even in the absence of production. Additionally, it touches on the concept briefly in Part D, implying a situation where there are no areas to demonstrate certain economic behaviors or outcomes.
• 16:00 - 24:00: Graph G3 Analysis The chapter 'Graph G3 Analysis' discusses the concept of a firm shifting down to a point where Q* (quantity produced or consumed) is zero units. This situation is described as a point with no dimensions, implying that total revenue would also be zero dollars. However, the transcript highlights the lack of fixed cost visibility on the graph, which only shows average variable cost, average total cost, marginal cost, demand price, and marginal revenue. The discussion notes this absence of fixed costs and the implications for graph analysis, particularly how it affects understanding the graph's area representations.
• 24:00 - 25:00: Monopoly Behavior in Short Run This chapter explores the concept of monopoly behavior in the short run. It delves into the condition under which a monopoly decides to shut down operations, analyzing the relationship between zero units of production and total revenue. The chapter outlines how total revenue in such scenarios equals the price (P star) multiplied by zero units, resulting in zero dollars. It also discusses the relationship with total costs, highlighting fixed costs and economic losses, while incorporating economic notations and symbols to illustrate these points.
• 25:00 - 27:00: Conclusion and Recommendations The chapter titled "Conclusion and Recommendations" appears to involve a presentation or discussion involving financial or economic analysis. It includes references to changing fonts and using mathematical symbols to represent economic losses and cash values. Specifically, the negative cash flow mentioned matches the fixed costs, highlighting the financial implications. The chapter seems to also address considerations over the long-run, although the context is provided for only one specific case.

ECON 2302 Example SR Firm Graphs/Graphing solutions (Unit 2) Transcription

• 00:00 - 00:30 good afternoon microeconomics students this is Professor Lewis here I am doing one other video besides oligopoly for unit two because we had some people that were absent the day that we covered how to solve the short-run graphs for those different businesses so this is to help them I'm not going to do the solution for all the short-run graphs in the practice problem set I'm going to do this the first three and so we're gonna be sharing the screen one more time here and so give me a moment to get this thing all put together well we're gonna
• 00:30 - 01:00 be doing here is we're gonna be going through how do you solve each of these graphs step by bloody step that's all idea here now one of the things we went over in class previously we talked about the fact that you have to look at the demand curve to answer the major questions the first question is which market structure is the firm producing under and this has to deal with how steep or flat the demand curve is this also kicks back to the unit 1 test problem 5 if you look at this demand curve here for G 1 you'll notice it has
• 01:00 - 01:30 a shallow negative slope that's not a monopoly they have a steep negative slope that's not perfect competition they have a horizontal demand so question hey here is monopolistic competition but you have to explain why it's monopolistic competition and I'm using some abbreviations you're allowed to use these leading and written by you of course be /c for because the man has a shallow negative slow ok question B
• 01:30 - 02:00 asks does this business producer shut down the short-run well the short-run shut down rule says that you compare P star to minimum average variable cost and if the price is strictly less than minimum average variable cost the firm shuts down if the price is greater than or equal you produce now there's only one curve that provides prices does anybody remember what that is it's the demand curve prices are gonna be read off the demand curve now
• 02:00 - 02:30 although price is variable we still have to compare a price to the average variable cost curve by comparing the altitude to the height of the demand relative to average variable cost if demand has a tangent point or intersects and cuts above average variable cost you've got quantities where price is bigger than minimum average variable cost and so it's better to produce but if the demand curve is always below the average variable cost you're gonna lose more money by producing it's better to shutdown so if you look at this demand
• 02:30 - 03:00 curve you notice here going top to bottom I'm always hitting average variable costs first going on these straight lines vertically the demand curve is always below the average variable cost so this means it's better to shut down so shuts down because D is below average variable cost using initials for those or all quantities every last one now Part C we work on this with our table problem anybody remember what happens in the firm shuts down it comes to a profit our loss well
• 03:00 - 03:30 the firm produces no no output but it still has to pay costs since the quantity of output sold is zero units the total revenue zero dollars and cents but the total cost is equal to the fixed costs so we're gonna have an economic loss we know that's immediately when the firm shuts down that's because these lefse firm all right now for Part D there to be no areas to show there's a reason for that
• 03:30 - 04:00 okay when the firm shifts down you had the following situation Q star is equal to zero units that's a point a point as no dimensions that therefore no area no length total car total revenues equal to zero dollars and cents should also be a point no dimensions total cost would equal a fixed cost but do you see any fixed cost in this graph we've got average variable average total and marginal cost demand which has priced Marshall revenue but there's no fixed costs on here we have nothing to show area wise we'd have to
• 04:00 - 04:30 say why no there is to show as q star is equal to well in the firm shuts down zero units total revenue is equal to P star time zero units equal to zero dollars and cents total cost is equal to the fixed costs and excuse me economic losses I need to borrow a Greek symbol here for one second one of our little deals on tight here's called cymbals I'm going to go
• 04:30 - 05:00 ahead and find that real quick there we go cymbal and then I gotta say negative PI equals and then we go back to Calibri okay pardon the font changes here I got to do this here okay Colibri and then I got to go red FC is a dollar value so it's reading round parentheses that means that the economic losses are in a negative cash value that matches fixed cost now we're gonna talk about long-run in this one case only
• 05:00 - 05:30 when a firm shuts down here's the situation they're losing so much money they're not producing anything they're not earning any revenue but they're having to eat their fixed costs after a while you know and entrepreneurs you just say this is crap this is garbage I'm not gonna keep doing this here why keep throwing money away when you can't sell anything now I realize there may be a few firms have a lot of money from the owner and they can still survive being shut down a long time but most business owners don't want to throw away money I deal with what's typical ninety five percent of time there's going to be no
• 05:30 - 06:00 long-run graph LRS for long run because firm is likely to exit the market in the long run I want you to notice we have no geometry here we have to explain why we have no longer in graph we have to explain why long run graphs are being handled in class okay but the thing is that's everything for graph G you want and the thing is if we had a perfect competition graph for the firm shutdown the short-run other than the fact that
• 06:00 - 06:30 the man will be horizontal we've got similar results written here and that's how you always handle a shutdown case now let's take a look at graph G to graph G to is a little bit different here first things first question a which market rips is a firm producing under that demand curve is horizontal that demand curve is sitting on the marginal revenue only one market structure has a horizontal demand curve which one is it problem five test one that is perfect
• 06:30 - 07:00 competition only perfect competition will have a horizontal demand curve so because the four demand is horizontal question B producer chef now the shorter run remember only demand provides price and in fact we got that P star from the equilibrium right there it's constant for this business now once you take a notice where my pointer is demand is intersecting average variable cost at least once in fact twice but in between you know this is a lot of values
• 07:00 - 07:30 there's a lot of values for prices above average variable costs of this firm is better producing than shutting down so produce you know party because the above average variable cost or some quantities doesn't have to be for all just for something now remember on that table problem we were comparing price to average total cost to determine if we should expect a profit or a loss while the demand curve here has our price and here's average total costs I want you to
• 07:30 - 08:00 clear that average total cost I want you to take a look the demand curve does this demand curve touch average total cost no it doesn't is this demand curve ever in the space above some values of average total cost no it isn't this demand curve is always below average total cost so since price is always less than average total cost its producing but it's gonna be an economic loss because demand is below average total cost for all quantities all quantities
• 08:00 - 08:30 not just some now for Part B we're gonna have to do some geometry here remember what happens when the business produces when the business produces what ends up happening is the following it is going to produce quantity Q star at price P star corresponding to M R being equal to MC remember demand and M arson on top of each other so here's marginal revenue and here's marginal cost on a graph M R is equal to MC where the two curves
• 08:30 - 09:00 intersect each other now here's how we're gonna find the right hand side boundary which will help us locate price so this one's already given to us and the average total cost to do some geometry here first things first I'm going to create this vertical line here I'm going to adjust the length of just a minute I'm also just how wide it is it's a little bit too thick and that's a little bit then that one's okay so I'm gonna move this line here whoops that's a spline I
• 09:00 - 09:30 don't want to spline I want to streamline so let's do this again here I'm gonna create this vertical line and I'm gonna move it to where it's passing through M R is equal to M C that's to the right of it that's where M C is equal to average total cost that's to the left of it here's where you Mar is equal to M see right there and the short knits that it doesn't go above the highest curve above it and you know what I think I may make this thinner here because it's kind of hard to see the corners there okay if you take a good look here let's zoom in for a moment
• 09:30 - 10:00 we'll zoom out you will notice here that mr is equally MC right here and that's where that line is okay and you notice that above it is the average total cost curve that's the highest curve above it and then we go to all the way down there's quality axis which is where it ends now I need to create some other items that can put in here because I have to put some corners here we've already got P star located so I do not need that okay what I do need however is I need to have a Q star for the optimal
• 10:00 - 10:30 quantity I need to have the letter C I need two corners a and B and I'll also be able to say ATC at Q star equals say what trust me it'll have become a little more apparent in a minute first of all let's talk about locating Q star let's make sure our selection is transparent that's important okay I'm gonna grab this Q star when I move it over to here notice Q star is now
• 10:30 - 11:00 directly below M are intersecting MC corner a is always used to find the price in which curve has the price if you said demand you're correct so corner a is where that demand curve is crossing the blue line P star is already found to our left so we don't have to locate it that's what's nice about perfect competition but we now have to find one more thing in that his corner B corner B is always on the average total cost curve directly above Q star corner a is used to find P star corner a is always
• 11:00 - 11:30 undemanding corner B is used to find average total cost per Q star corner B is always on the average total cost curve a B and Q star are all on the same line segment make sure they're lined up nice and when you do this and make sure you use a blue pen or pencil now this letter C is a dollar value it's the dollar value for the average total cost a quantity Q star the reason why we're using that letter C here is because it represents average total cost of Q star we're not producing zero units so our average total cost is
• 11:30 - 12:00 non zero the thing is average total cost equals total cost divided by quantity and since we have to represent this as the area of a rectangle and the area of a rectangle is length times width average total cost times quantity will equal the total cost and so I'm gonna go over here to corner B then I create a horizontal blue line I'm gonna just it just a little bit here until it gets to be easily visible now I want you to notice that I've gone straight horizontal left from corner beads the dollar axis and excuse me I did not mean to make that one there and
• 12:00 - 12:30 this is going to be the average total cost of quantity Q starts this marker right here okay and that's what letter C stands for all right zooming back out now okay we need to answer question D using geometry so I'm gonna start by saying total revenue total revenue is equal to price times quantity excuse me P star times Q star the length of the segment
• 12:30 - 13:00 from a zero to P star is price the length of second from zero to Q star is quantity and so the area of this rectangle we start lower left hand go and go counter clock and go clockwise excuse me from 0 up to P star over 2a and down in Houston that big rectangle on the bottom is gonna equal to total revenue so your right area and I don't have a rectangle symbol I don't think let me see if I can come up with one though probably not but you never really know you know what I don't want to mess with this here I'm just gonna write the word rectangle you use a rectangle
• 13:00 - 13:30 symbol it looks like a rectangle if you like from zero the corner P star the corner a the corner Q star that's equal to total revenue total cost is equal to average total cost on quality which is C times Q star okay C times Q star I don't have a multiplication symbol here mister X and here just for now I don't like the use of X it should be the algebra one not the one from arithmetic the length of the segment from the origin to letter
• 13:30 - 14:00 C that length is equal to C the average total cost for Q star the length of the segment from 0 to Q star that length is Q star so starting at 0 the area of the rectangle from 0 to C to B to Q star is average total cost times quantity it is therefore total cost area rectangles 0 CB Q star now I watch I notice 0 CB Q star total cost is slightly bigger than 0 P star aq star total revenue and
• 14:00 - 14:30 notice we've got a skinny little rectangle in between where I'm moving my pointer that skinny little rectangle in between is the degree to which total cost was bigger than torille revenue that is our economic losses and we're not going to use red here because this is not cash this is areas areas can't be negative but we're going to be using our symbols here and so forth just so that we're consistent but the thing is we're not using any red ink they will have numbers when off cash we're going to do this just strictly as an area the
• 14:30 - 15:00 magnitude of that area matches the economic loss that's TR minus TC with a negative result that's the area of the rectangle the lower left hand corner that's Neil or rectangle is P star there's usually let me adjust my spacing here the next one is C and then going to the right is B remember we're going clockwise same direction the clock goes remember and actually and then at a is the lower right hand corner so the skinny little rectangular area that is
• 15:00 - 15:30 equal to the total the probably the economic losses to the firm now that's all for Part B because this firm is producing in the short-run it will have a long-run graph and the long-run graph for this one would be the same as the long-run graph for a perfect competition business that produces in the short-run at a profit they're going to end up with the same situation because of long-run adjustments to the market now I'd also say that we could have had a situation with a monopolistic
• 15:30 - 16:00 competition firm producing in the short of profit or a loss and again as long as the firm produces and short-run it will have a long-run riff the long-run outcome from Annapolis to competition whether produce at a profit or produce at a loss will be the same but for any firm that shuts down the short-run the long-run result is there is no long run graph that business is likely the eggs at the market G to that firm will have a long-run graph it is not likely to exit the market now let's move on and talk about g3 g3 is very
• 16:00 - 16:30 interesting here now the first question is which market structure is this business producing under I'll take a look at the demand curve for the mane curve is a steep negative slope which means that it's a monopoly but do we see AP reg labeled on here anyway if there is a regulated monopoly there'd be like a P reg going to the demand curve the dollar axis and the horizontal line I don't see it do you well of course not this is not a regulated monopoly there is no P rigged so this is a pure monopoly we need to
• 16:30 - 17:00 say why here because D has a steep negative slope and no P reg no regulated price is present now question B as this firm produce are shutting down the short-run take a look at the demand curve here it is with a d take a look at the average variable cost with the AVC on the end notice demand intersects average variable cost and it goes above it as
• 17:00 - 17:30 long as demand at least touches average variable cost or intersects and goes above it the firm is better off producing than shutting down so produce in short run because D is above average variable costs are in shut down the rule application or some quantities okay question see economic profit or economic loss we compare a price to average total cost only the man provides prices I
• 17:30 - 18:00 repeat only demand provides prices I want you all to notice here's average total cost demanding average total cost intersect each other to the left of that intersection point the demand is clearly a lot higher than the average total cost which means there are prices at which this business can sell products where the price per unit is higher than the average total cost per unit that tells you profit as possible so economic profit because D is above average total cost for some one of these and Part B we're
• 18:00 - 18:30 about to get to a might actually put that in in just a second here that's gonna be our geometry problem this is not a regulated monopoly they have a different rule than everybody else has this is a pure of monopoly and so just like any other structure if the fur produces this one does you choose Q star and P star corresponding to M R be equal MC here's marginal cost here's marginal revenue they're equal to each other at this point of intersection
• 18:30 - 19:00 and so what we're gonna do is we're constructing rid of a line that's going to start at the highest curve above that intersection and this time that's the demand curve and that's gonna pass through mrmc and I think I've just about got in the lined of them just move it a little bit to the left there we go and let me make it a little bit thicker here so I'm not zoomed in like I was before gamma R equals MC is what we use to find the line you would take your protractor straightedge and you would set it so that it's perpendicular to the quantity axis the horizontal axis is called Q for
• 19:00 - 19:30 quantity and it goes from the highest curve above it which this time is demand passes through mRNA checking MC and stops at the quantity axis alright this is our right hand side boundary for our rectangles now P star has to be located this time Q star has to be located as well okay we also need to find corner a we need to find corner B we need to find value C and value C is equal to average total cost use me our total cost at Q
• 19:30 - 20:00 star which is equal to value C alrighty so I need to have these ready to go Q star is found where m r is equal to MC where do I put this Q star does it go here does it go there does it go over a year no silly it goes on the quantity axis directly below mr glim see that's your optimal profit maximizing the loads quantity corner a is used to find P star which graph has P star only one graph
• 20:00 - 20:30 has price is that is the demand curve Corner a is with a blue line crosses demand so to find P star we do our straight line you do a horizontal line going from corner a on the demand curve that blue line crosses it above U star and then go the dollar axis and stop at the dollar actions the vertical axis is dollars prices aren't the only thing measured in dollars you also are costs remember that's way called the dollar axis or vertical if you prefer so there is P
• 20:30 - 21:00 star we now have our rectangle for total revenue what's the next thing we need to find we need to express total cost as a product of two numbers it's going to be what x quantity that's right it's going to be the average total cost times the quantity that's a dollar value but we need to reference corner to find it and that is reference corner B a B and Q star collinear corner B is where the blue line crosses the average total cost
• 21:00 - 21:30 corner a is with a blue line intersects demand all right and so before I actually move this need to go right out to go from corner B horizontally to the left to the dollar axis okay that is average total cost at Q star okay which is equal to C letter C equals average total cost a quantity Q star now that the architecture is in place we can talk rectangles once again
• 21:30 - 22:00 rectangles okay so let me just get this thing cut set up just so your Part D total revenue is equal to P star times Q star lengths are the same where from 0 to P star its price length of the segment was 0 to Q stars quantity it forms a rectangle starting at the origin going up to P star over 2a and down to Q star everybody has to do this clockwise from the lower left hand corner that's the area of rectangle 0 P star a Q star
• 22:00 - 22:30 and remember go clockwise same direction the clock outs total cost is equal to average total cost times quantity which is C times Q star notice here that C is not a tie up as it wasn't last graph here because average total cost is less than prices we're making a profit the length of this segment from zero to C is average total cost is zero to Q star is total cost is quantity Part B so the area rectangle 0 CB Q star this
• 22:30 - 23:00 rectangle the bottom okay that's equal to the total cost notice this big rectangles area is total revenue notice the smaller rectangle the bottom is total cost the difference between the two of them is this smaller rectangle at the top this rectangular area is how much total revenues bigger than total cost that's our economic profit so I need just change my font just one time more year and where do you simple
• 23:00 - 23:30 yep got to use symbol here because that's what those pies are found by excuse me equals we're gonna go back to Calibri TR minus TC lower left-hand corner is letter C let me go clockwise up here area rectangle C P star a ADB alrighty so that's the answer of section
• 23:30 - 24:00 D and now we've got all the short-run stuff done but let me make a couple of comments here you're not gonna see up here monopoly producing in the short run on a loss or shutting down for a loss those are examples what you call tax evasion and a scam they're not legitimate a pure monopoly will be producing in the short run and an economic profit and that's the only way the pure monopoly is gonna work the others are facetious yes they're possible but they're not are likely less than 1 percent chance of that are really happening and we're gonna deal with the real world exclusively here alrighty the
• 24:00 - 24:30 thing is you know regulated monopolies have a different rule but they'll also be produced in the short run out of economic profit but it won't have the same boundaries because they lose their control over their price this P star man that's kind of big there okay and that Q star leaves a bigger profit if they produce to the lower price that rectangle B flat they'd have more output but as that rectangle flattens that area gets smaller this is the maximum profit possible if they produced at a higher price versus the output it would the right hand will get skinnier in the area
• 24:30 - 25:00 with shrinking so this is the best size for it to be given the configuration of these graphs any graph that produces in the short run will have a long-run graph and so I'm going to scroll back up we take a look at what we had here in each case and so forth and these are just examples here but again question a question B question C are all based on demand curve slant R tilde the demand curve and with a monopoly is there appear egg present or absent position of demand versus average
• 25:00 - 25:30 variable cost to determine producer shut down position of demand versus average total cost average variables for shutdown are produced average totals for profit or loss when we produce of course if we know we're shutting down we immediately know it's an economic loss there's no debate or discussion when that goes down okay and then everything we did here to find P star Q star was based upon the intersection of mrmc and then finding a right hand side boundary that starts the highest curve above it again only when we produce passes
• 25:30 - 26:00 through Michael MC it stops at the quantity axis and that's how we solve these things already so we're gonna go back over here and stop sharing the screen here and we'll wrap this thing up didn't mean for this to go so long but at the same time because of people being absent this is gonna be useful it's not all the answers to all the problems in that practice problem set but it's a good way to get started slide show number four and slide show number five have the optimization rules for regulated monopolies make sure you
• 26:00 - 26:30 study them they're not the same as pure because again they lose price control and also slide show number five does have the long run graphs where applicable so good luck to everybody success y'all I'll see you later