Question

Debi had $1.55 in a collection of dimes and nickels. The number of nickels is seven more than the number of dimes. Find the number of each type of coin.

There are ___ dimes.
There are ___ nickels.

Answer 1

N =D+7

0.10D +0.05(D+7) = 1.55

0.15D +0.35 = 1.55

0.15D=1.20

D=120/0.15 = 8

8x0.10 = 0.80

1.55-0.80= 0.75

8+7=15 * 0.05 = 0.75

8 dimes and 15 nickels