Marcus deposits 1300$ into into an account that earns 4% simple annual interest. What is the balance in his account after 21 months?
4/100 x $1,300 =$52 simple interest for 1 year.
$52/12 =$4.33 simple interest for 1 month.
$4.33 x 21 =$90.93 simple interest for 21 months.
$1,300 + $90.93 =$1,390.93 balance of the account after 21 months.
