Question

Isaiah has $7.15 in Dimes and Nickels. He has a total of 91 coins. How many of each coin does he have? Group of answer choices dimes: 31 nickels 60 dimes: 60 nickels: 31 dimes: 52 nickels: 39 dimes: 39 nickels: 52

Answer 1

Dimes = x = 52

Nickels = y = 39

Explanation:

Let

Dimes = x

Nickels = y

x + y = 91 (1)

0.10x + 0.05y = 7.15 (2)

From (1)

x = 91 - y

Substitute x = 91 - y into (2)

0.10x + 0.05y = 7.15

0.10(91 - y) + 0.05y = 7.15

9.10 - 0.10y + 0.05y = 7.15

- 0.10y + 0.05y = 7.15 - 9.10

-0.05y = -1.95

y = -1.95 / 0.05

= 39

Substitute y = 39 into (1)

x + y = 91

x + 39 = 91

x = 91 - 39

x = 52

Dimes = x = 52

Nickels = y = 39