4-111. Suppose you owe $1,100 on your credit card. The annual percentage rate (APR) is 18%, compounded monthly. The credit card company says your minimum monthly payment is $19.80. (4.15)

a. If you make only this minimum payment, how long will it take for you to repay the $1,100 balance (assuming no more charges are made)?

b. If you make the minimum payment plus $10 extra each month (for a total of $29.80), how long will it take to repay the $1,100 balance?

c. Compare the total interest paid in Part

(a) with the total interest paid in Part (b).