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| Question 459575:  Please help me solve this problem. The Davis Company manufactures a product that has a unit selling price of $20 and a unit cost of $15. If fixed costs are $600,000 , determine the least number of units that must be sold for the company to have a profit.
 Answer by math-vortex(648)
      (Show Source): 
You can put this solution on YOUR website! The big idea we will use to solve this problem is that the Davis Company will make a profit when their income exceeds their expenses. Let
 n = number of units sold
 I = income from selling n units
 E = expenses for selling n units
 We need two equations--one for income, one for expense--in terms of n
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 INCOME is the number of units Davis sold times the selling price
 I = 20n
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 EXPENSES are the fixed costs plus the number of units Davis sold times the unit cost
 E = 600,000 + 15n
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 We want to know when income exceeds expenses. Here's how we say that mathematically:
 I > E
 .
 Now it's a simple matter of substituting the equivalent expressions we have for I and E. We get
 20n > 6000,000 + 15n
 '
 Solve for n to find the appropriate values for n
 20n - 15n > 500,000
 5n > 600,000
 n > 120,000
 We interpret this to mean that when n > 120,000, the income will exceed expenses. So, 120,001 is the least number of units Davis must sell to make a profit.
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 CHECK
 It's always a good idea to check our answers. Substitute 120,000 for n in the income and expense equations.
 I = 20n = 20(120,000) = 2,400,000
 E = 600,000 + 15n = 600,000 + 15(120,000) = 2,400,000
 We see that when Davis sells exactly 120,000 units, income and expense are equal. This is the break even point.
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 However, if Davis sells 120,001 units, look what happens:
 I = 20(120,010) = 2,400,020
 E = 600,000 + 15(120,001) = 2,400,015
 The income is $5 more than the expenses. The Davis Company has made a profit.
 
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