Answer:
14 quarters and 28 nickels
Step-by-step 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.
