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Question 120834:  A store can purchase shirts for $7 each.  It has fixed costs of $2,500.  Each shirt is sold for $18. 
1.  Write a linear equation for both cost and revenue. 
2.  Graph both cost line and revenue line. 
3.  Determine the break-even point.  
4.  If the store wants to make a profit of $2,000, how many shirts must it sell?
 
Textbook is McDougal Littell 
Algebra 1 
Chapter 5 Resource Book 
Page 19 
 Answer by ankor@dixie-net.com(22740)      (Show Source): 
You can  put this solution on YOUR website! A store can purchase shirts for $7 each. It has fixed costs of $2,500. Each shirt is sold for $18. 
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Let x = no. of shirts 
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1. Write a linear equation for both cost and revenue. 
Cost: 
The total cost consist of the fixed cost and the wholesale cost of each shirt. 
C(x) = 7x + 2500 
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Revenue: 
Consists of the number of shirts sold times the $18 retail price of each 
R(x) = 18x 
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2. Graph both cost line and revenue line. 
Cost line: y = C(x) 
y = 7x + 2500; purple line 
Revenue line: 
y = R(x) 
y = 18x; Green 
Plot these x = 0 and x=300 
Graphing these: 
  
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3. Determine the break-even point. 
That will be where the graphs intersect, approx: x=230 shirts sold 
You can find out exactly: Break even occurs when Revenue = Cost 
18x = 7x+2500 
Solve for x to find the exact break-even point 
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4. If the store wants to make a profit of $2,000, how many shirts must it sell? 
Profit is Revenue - cost: 
18x - (7x + 2500) = 2000; solve for x 
18x - 7x - 2500 = 2000 
18x - 7x = 2000 + 2500 
11x = 4500 
x = 4500/11 
x = 409.1 or 410 shirts will make a 2000 profit 
Check that: 
18(410) - 7(410) - 2500 
7380 - 2370 - 2500 = $2010, we can't sell a fraction of a shirt 
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Did this shed some light on this cost, revenue, profit, stuff. 
Any questions?  
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