Answer:
With a principal = 7200$, interest rate = 14.25% = 0.1425 (compounded quarterly), the amount of money(M) after n years is calculated by formula:
M = Principal x (1 + rate)^time
= 7200 x (1 + 0.1425/4)^(nx4)
(the rate is divided by 4 and the time is year x 4, because this is compounded quarterly, 1 year has 4 quarters, each quarter has 3 months)
=> After 3 years:
M = 7200 x (1 + 0.1425/4)^(3x4) = 10958.7951$
=> After 10 years:
M = 7200 x (1 + 0.1425/4)^(10x4) =29203.4074$
=> After 14 years:
M = 7200 x (1 + 0.1425/4)^(14x4) = 51129.7818$
=> After 20 years:
M = 7200 x (1 + 0.1425/4)^(20x4) = 118449.862$
Hope this helps!