Question

Jenya has 12 bills in her wallet. She has a total of $82. If she has twice as many $5 bill as $1 bills, and two more $10 bills than $5 bills, how many of each does she have?

Answer 1

You can use logic to say right off the bat that you have 2 one dollar bills
if you said you had 7 instead there would be not enough bills to add up to 82

so that means 4 $5 and 6 $10

check you have 12 bills and it adds up to $82

2 $1  
4 $5
6 $10