Question

Ivan bought 35 stamps. Some of these stamps cost $0.15 each, and the rest cost $0.40 each. If the total value of the stamps he bought is $7.25, determine the number of $0.15 stamps that Ivan bought.

Answer 1

27

Explanation:

Let x represent the number of $0.15 stamps Ivan bought. Then the value of his stamps is ...

0.15x +0.40(35-x) = 7.25

-0.25x +14.00 = 7.25 . . . . . eliminate parentheses, collect terms

-0.25x = -6.75 . . . . . . . . . . . subtract 14.00

x = 27 . . . . . . . . . . . . . . . . . . divide by -0.25

Ivan bought 27 $0.15 stamps.