### Home > CCA2 > Chapter B > Lesson B.1.4 > ProblemB-51

B-51.

Jerry says, “I’ve got my money in a great account that compounds interest monthly. The equation $y = 388\left(1.008\right)^{m}$ represents how much money I have at the end of any month.” What is Jerry’s monthly interest rate? Write an equation to represent your total money if you invest $500$ in an account with the same rate of return. Let $m$ represent the number of months the money has been invested.

The monthly interest rate can be found using the multiplier.
Subtract $1$ from the multiplier: $1.008 − 1 = 0.008$
Change the decimal to a percent: $0.008·100\%=0.8\%$
Make $500$ the original investment in the equation.

Monthly Interest Rate: $0.8\%$

$y = 500\left(1.008\right)^{m}$