Question

Audrey has 32 dimes and quarters in her piggy bank with a total value of $6.50. how many of the coins are dimes and how many are quarters?

Answer 1

d + q = 32....d = 32 - q
0.10d + 0.25q = 6.50

0.10(32 - q) + 0.25q = 6.50
3.20 - 0.10q + 0.25q = 6.50
-0.10q + 0.25q = 6.50 - 3.20
0.15q = 3.30
q = 3.30 / 0.15
q = 22 <===  22 quarters

d + q = 32
d + 22= 32
d = 32 - 22
d = 10 <=== 10 dimes