Question

Paul has a collection of nickels and dimes that has a total value of

$12.50. He has 150 coins in all. How many dimes does Paul have?

50

75

100

134

Answer 1

100 dimes.

Explanation:

Two equations.

First modeling the total money with x as nickels and y as dimes.

0.05x + 0.1y = 12.50

Second, modeling the amount of coins.

x + y = 150

Which you can alter to substitute for in the first equation.

x = 150 - y

Subsitute.

0.05(150 - y) + 0.1y = 12.50

7.5 - 0.05y + 0.1y = 12.50

0.05y = 5

y = 100

Paul has 100 dimes and 50 nickels.