Kyle recently received a credit card with an 18% nominal annual interest rate. With the card, he purchased an Apple iPhone for $600. The minimum payment on the card is $20 per month.

a) If Kyle makes the minimum monthly payment and makes no other charges, how many months will it be before he pays off the card? Round your answer to the nearest whole month. (show the answer on Excel, and use Excel function)

b) If instead, Kyle makes monthly payments of $30, how many months will it be before he pays off the debt? Round your answer to the nearest whole month. (show the answer on Excel, and use Excel function)

c) Kyle wants to finish paying off in just one year. He found an internet offer from a company willing to pay off his credit card balance if he pays them $50 per month for 12 months. Is this a good deal for Simon? (show the answer on Excel, and use Excel function)