Parents wish to accumulate $50,000 at the end of 20 years for a college fund for their child. They contribute once at the end of each year. Assuming the fund earns a fixed effective interest rate of 7% annually, answer the following questions:
(a) How much do they need to contribute assuming equal contributions.
(b) If they contribute 1000$ for the first 10 years, and X for the remaining 10 years, find the value of X.