A full-time worker aged 35 invests $750 a month in a fund which has an average yearly return of 8.4% compounded monthly. (a) The worker wants to estimate what they will have for retirement when they are 60 years old if the rate stays constant. Assume monthly compounding. (b) If the worker makes no further deposits and makes no withdrawals after age 60, how much will they have for retirement at age 74?