Two payments of $5000 are scheduled six months and three years from now. They are to be

Question:

Two payments of $5000 are scheduled six months and three years from now. They are to be replaced by a payment of $3000 in two years, a second payment in 42 months, and a third payment, twice as large as the second, in five years. What should the last two payments be if money is worth 9% compounded semiannually?