Show all work and formulas

6) Sue has obtained a personal loan of $5000 at 13.25% simple interest for 4 years. She paid all the monthly payments except the last five payments, which she wants to pay all at once.

a) What is the total of these last five payments?

b) How much would the bank want her to pay, after revealing that her loan contract carries a pre-payment penalty?

c) How much would that penalty be?