Question

A boy has 11 coins in dimes and quarters. Their value is $170. How many of each does he have? (Hint: Let x be the number of quarters and 11 - x be the number of dimes.)​

Answer 1

x - number of dimes, y - number of quarters

x + y = 11

0.10 x + 0.25 y = 1.70

0.10 x + 0.25 ( 11 - x ) = 1.70

We can solve it:

0.10 x + 2.75 x - 0.25 x = 1.70

0.15 x = 1.05

x = 1.05 : 0.15

x = 7 ( a boy has 7 dimes and 4 quarters )

Answer: D ) 0.10 x + 0.25 ( 11 - x ) = 1.70

Explanation: