Bob has half as many quarters as dimes. He has $3.60. How many of each coin does he have?

Bob has half as many quarters as dimes. He has $3.60. How many of each coin does he have?

Let q be the number of quarters. Let d be the number of dimes. We're given:

1. q = 0.5d
2. 0.25q + 0.10d = 3.60

Substitute (1) into (2):
0.25(0.5d) + 0.10d = 3.60
0.125d + 0.1d = 3.6

Combine like terms:
0.225d = 3.6

Typing this equation into our search engine, we're given:
d = 16

Substitute d = 16 into Equation (1):
q = 0.5(16)
q = 8