Answer:
- I = 10b; b is defined in the problem statement; 10 is the price of a book
- E = 3b-70; 3 is the cost of producing a book; 70 is fixed cost
- P = 7b -70
- P = 280 . . . . profit from 50 books
Explanation:
This question requires you make unsupported assumptions.
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If you assume the given profit expression expresses the difference between revenue (R) and cost (C):
P = R - C
then you can associate the terms as follows:
R = 10b
C = 3b +70
a) The income (revenue) might be ...
income = 10b
"b" is defined as the number of books sold. This suggests that "10" is the income produced by selling one book.
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b) The expenses (cost) might be ...
E = 3b +70
"b" has the same definition as before. We suppose "3" is the marginal cost of producing one book, and "70" is the fixed cost of operation whether books are produced or not.
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c) The given profit equation simplifies to ...
P = 7b -70
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d) The profit for selling 50 books is found by putting 50 where b is in the equation and doing the arithmetic.
P = 7·50 -70
P = 280 . . . . profit for selling 50 books