Initial amount= $5080.
Interes rate=21%
The final quatity is given by:
Where,
PV= initial amount= $5080
i=rate of interest =21%
n= time in years =3 years
Replacing:
He has to pay $279.66 each month.
B) Total interest.
Final amount-initial amount:
The total interest he had to pay is: $4987.76.