Question

Mary has a collection of nickels and quarters for a total of $4.90. If she has 42 coins in total, how many of each kind are there?

Answer 1

14 quarters and 28 nickels

Explanation:

System of Equations where x = number of quarters and y = number of nickels

(1) equation with value of each coin

0.25(x)+0.05(y) = 4.90

(2) total number of coins

x + y = 42

Solve system of equations using either substitution or elimination

(elimination multiplying equation 2 by -0.5)

.25(x) + 0.05(y) = 4.90

-0.05(x) - 0.05(y) = 42 * (-0.05)

(3) Resulting equation

.20(x) = 2.8

x = 14

plug x into equation 2

14 + y = 42

y = 28

There are 14 quarters and 28 nickels in Mary's collection.