Sang-jin has only quarters and nickels in her piggy bank. she has 66 coins in the bank with a value of $11.50.
how many quarters are in sang-jin’s piggy bank?
enter your answer in the box.

Let x be quarters, and y be nickels.
0.25x + 0.05y = 11.50

x + y = 66

x= 66 - y

0.25(66-y)+0.05y=11.50
16.5 -0.25y+0.05y = 11.50
16.5-0.2y=11.50
-0.2y=11.50-16.5
-0.2y=-5
-0.2y/-0.22=-5/-0.2
y=25

x+y=66
x+(25)=66
x=66-25
x=41

So there are 41 quarters, and 25 nickels.