Solve the following problems involving annuities.

a) Craig invests $200 on the last day of each month starting in January 2017. If he earns 5% interest, when will his accumulated value first exceed $5000?

b) A credit card charges interest of a nominal rate of 18% compounded monthly. Maria has a balance outstanding of $4000 and plans to repay it with monthly payments of $400 starting today. How long until she repays the amount owing? How much interest does she pay over this time?

c) Find the present value on December 31, 2017 of payments of $50,000 due to be paid on the last day of 2020, 2023, 2026 and 2029. Use 4% interest.