A cash box has $5 bills and $10 bills totaling $450. There are 8 times as many $5 bills as $10 bills. How many bills are in the box?

Question

I need the answer to how many bills are in the box

Answer 1

There are (at least) two ways to solve this problem.

 

First, there are 8 $5 bills for every $10 bill.  Add them together, and those 9 bills equal $50.  So set up a proportion

 

$50/9 = $450/x

$50x = $4050

x = 81 bills

 

Note:  this works well because there are no bill fractions in the cash box.

 

Second, let x=the number of $5 bills and y=the number of $10 bills:

 

x = 8y

5x + 10y = 450

 

substitute for x

 

5(8y) + 10y = 450

40 y + 10y = 450

50y = 450

y = 9

x = 8(9) = 72

9 + 72 = 81 bills