Coin Problem

Betty has 10 more dimes than quarters. If she has $3.45, how many coins does she have?
How many quarters and how many dimes?

x = # of quarters
x + 10 = # of dimes

.25x + .1(x + 10) = 3.45 {value of each multiplied by # of each equals total value}
.25x + .1x + 1 = 3.45 {used distributive property}
.35x + 1 = 3.45 {combined like terms}
.35x = 2.45 {subtracted 1 from both sides}
x = 7 quarters {divided both sides by .35}
x + 10 = 17 dimes {substituted 7 in for x into x + 10}
7 quarters and 17 dimes

- Algebra House