Question

The value of 110 coins, consisting of dimes and quarters, is $20.30. how many of each kind of coin are there?

Answer 1

D + q = 110......d = 110 - q
0.10d + 0.25q = 20.30

0.10(110 - q) + 0.25q = 20.30
11 - 0.10q + 0.25q = 20.30
-0.10q + 0.25q = 20.30 - 11
0.15q = 9.30
q = 9.30/0.15
q = 62 <==== there are 62 quarters

d = 110 - q
d = 110 - 62
d = 48 <==== there are 48 dimes