You would like to have ​$70,000 in 16 years. To accumulate this​ amount, you plan to deposit an equal sum in the bank each year that will earn

10 percent interest compounded annually. Your first payment will be made at the end of the year.
a.How much must you deposit annually to accumulate this​ amount?
b.If you decide to make a large​ lump-sum deposit today instead of the annual​ deposits, how large should the​ lump-sum deposit​ be? ​ (Assume you can earn 10 percent on this​ deposit.)
c.At the end of year​ 5, you will receive ​$20,000 and deposit it in the bank in an effort to reach your goal of ​$70,000 at the end of year 16.

In addition to the​ lump-sum deposit, how much must you invest in 16 equal annual deposits to reach your​ goal?​