Can you help me on the backsolving question 7 on pg. 37? Its got me stumped even with the backsolving.

Sure! I trust you already looked at the solution in the back, which walks through the backsolve, so maybe I’ll show you the algebra?

Let’s say s is the number of subway trips and c is the number of car trips. She commutes 5 days, so she takes 10 total trips: s+c=10. We also know she spends a total of $74.75, so our second equation is 2.75s+18.5c=74.75. Solve the system!


Leave a Reply