Money Problems

Question

A cash register contains only ten dollar and twenty dollar bills. It contains three times as many ten dollar bills as twenty dollar bills and the total amount of money in the cash register is $2,100. How many ten dollar bills are in the cash register?

Answer 1

We know nothing about the $20 bills, so call it X

THEN there are 3x $10 bills, since there's 3 times as many

 

(3x)($10) + $20x = 2100

 

 30x + 20x = 2100

 

 50x = 2100

 

x= 42

 

CHECK:

 42 x $20 + 126 x $10 = $840 + 1260 = $2100