CPM Homework Banner

Home > CC3 > Chapter 9 > Lesson 9.1.3 > Problem 9-37


Joaquin has agreed to lend his younger brother so that he can buy a new tank for his pet lizard.

  1. Joaquin is charging his brother simple interest per month. If his brother pays him back in 6 months, how much will Joaquin get back?

    Using the equation for simple interest:

    Remember, the total money Joaquin gets back includes the principal and the interest.

  2. If Joaquin’s brother instead borrowed the money from a bank at  compound interest per month, how much would he have to pay the bank at the end of 6 months?

    Use the equation for compound interest: