Basic Math Help

Question

A student makes a $9.25 purchase at the bookstore with a $20 bill.The store has no bills and gives the change in quarters and fifty-cent pieces. There are 30 coins in all. How many of each kind are there?

 

How many quarters are there in change?

Answer 1

Change received :

$20-$9.25 = $10.75

 

Set up two simultaneous equations:

10.75 = a(0.25) + b(0.50)

a + b = 30

 

Solving gives:

a = 17, b = 13

Where a is the number of quarters and b is the number of fifty-cent pieces