Assistance needed. Having difficult time recognizing the necessary formula and how to use it to answer the questions. Thank You

A 40-year-old, unmarried client has been contributing to an HSA for the last three years using a salary reduction agreement through his employer. The stated effective annual rate on the account is 3% and the interest is compounded on a monthly basis. The client is in the 25% marginal federal tax bracket and the 5% marginal state tax bracket. Use this information to answer the following questions.

a. How much money does the client currently have in the HSA if the client has deposited $ 200 per month and did not make any withdrawals?

b. Because the client is in exceptionally good health, the client is also using this account as an additional retirement savings vehicle. How much money will the client have in the account at age 65 if the client maintains his current level of contribution?

c. How much will the client have at age 65 if the client contributes $ 2,850 every year?

d. How much will the client have at age 65 if the client contributes $ 2,850 every year if it is assumed that the contribution and catch-up provision limits increases to 2.5% each year? (Ignore any minimum or maximum dollar change limitations.)