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

She has 2-1s, 4-5s and 6-10s. 

You can assume that she must have a number of 1s equal to a multiple of 5 with 2 added since that is the only way to get a number ending in 2. Starting with the obvious starter 2, this would work and add to the appropriate total.