Question

A woman has 31 coins in her pocket, all of which are dimes and quarters. If the total value of the coins is $ 5.65, how many dimes and how many quarters does she have?

Answer 1

14 dimes and 17 quarters

Explanation:

d and q are the number of dimes and quarters, respectively.

"31 coins, all of which are dimes and quarters."

d+q = 31

d = 31-q

"the value of the coins is $5.65"

0.10d + 0.25q = 5.65

substitution

0.10(31-q) + 0.25q = 5.65

3.10-0.10q + 0.25q = 5.65

0.15q = 2.55

q = 17

d = 31-q = 14

14 dimes and 17 quarters