Question 207143
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Let *[tex \Large x] represent the number of pamphlets purchased.  Then *[tex \Large x - 20] must represent the number of books purchased.


Each pamphlet costs 5 cents, so the total amount paid for pamphlets must be *[tex \Large 5x] cents.  Each book costs 40 cents, so the total amount paid for books must be *[tex \Large 40(x-20)].  And the sum of these two amounts is $4.15, which we can represent at 415 cents so that the units of measure are consistent.  (alternatively, you could say that the total cost of pamphlets was *[tex \Large 0.05x] and the total cost of books *[tex \Large 0.40(x-20)] and then the sum would be 4.15, but I just like to work with integer coefficients)


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ 5x + 40(x - 20) = 415]


Solve for *[tex \Large x] and you have your answer.


John
*[tex \LARGE e^{i\pi} + 1 = 0]
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