Stretch
1. John has 15 bills in his wallet that total $145. He has a mix of five-dollar bills, ten-dollar bills, and twenty-
dollar bills. The number of ten-dollar bills is one less than twice the number of twenty-dollar bills.
a. Write a system of three linear equations in three variables to represent this situation. Be sure to
define your variables.
b. How many of each denomination does John have in his wallet? Solve this system using Gaussian
elimination.