Carter has $3 in a savings account that earns 7% interest per year. The interest is not compounded. How much will he have in 4 months?
Formula
A = P + Prt
Where A is the final amount
P = amt invested = $3
r = interest rate per year = 7% = .07
t = (1/3) yr
So we have
A = 3 + 3(.07)(1/3) = 3 + 3(.07) = $3.21
CPhill: There is a minor typo in the answer. $3 x 0.07 =0.21 cents for 1 full year.
So, for 4 months or 1/3 of a year =$3 + 0.21/3 =$3.07 - principal + interest for 4 months.
+23 
