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Economics, 6/e
Stephen L. Slavin

Perfect Competition

Extra Help with Math & Graphs

Chapter 22. Perfect Competition

# 1: Calculating Total Profit Using a Graph

We're going to use data from Figure 22.1 to calculate the total profit of this perfect competitor. We'll be using this formula: Total Profit = Output (Price - ATC). Please look at the graph and write down the output, price, and ATC.

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Figure 22.1

The output is 65 (where MC and MR intersect). At that output ATC = $11. And price, which is read from the demand curve, D, is $14. Now plug the numbers into the formula and solve for total profit.

Solution:

Total Profit  =  Output (Price - ATC)
  = 65 ($14 - $11)
  = 65 ($3)
  =  $195

#2: Calculating Total Loss Using a Graph

Use the data in Figure 22.2 to find this firm's total loss (i.e., negative total profit).

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Figure 22.2

Total Profit  =  Output (Price - ATC)
  = 13 ($10 - $13)
  = 13 (-$3)
  =  -$39