CPM Homework Help : MC2 Problem 9-21

Joaquin has agreed to lend his younger brother $$45$ so that he can buy a new tank for his pet lizard. Joaquin is charging his brother $2\%$ simple interest per month. If his brother pays him back in $6$ months, how much will Joaquin get back?

Help:

Using the equation for simple interest:

Interest $= Prt$
$P =$ principal
r $=$ interest rate
$t =$ time

Hint:

Interest $= $45$ ( $.02$ )( $6$ months)

Answer:

$$50.40$
Remember, the total money Joaquin gets back includes the principal and the interest.