The trustees of a college have accepted a gift of $150,000. The donor has directed the trustees to deposit the money in an account paying 6% per year, compounded semiannually. The trustees may withdraw an equal amount of money at the end of each 6-month period; the money must last 5 years.
(a) Find the amount of each withdrawal.
(b) Find the amount of each withdrawal if the money must last 7 years.