a.In return for payments of $200 at the end of 5 years and $300 at the end of 10 years, a man agrees to pay X at the end of 3 years and 2X at the end of 6 years. Determine X if d = 3.5%.

b.The present value of two payments of 100 each to be made at the end of n years and 2n years is 100. If i = .035, determine n.