4. (3+3+4 points). (a) $4,500 will be paid 6 years and 10 months from now. Find the present value of this payment if interest is at j2 = 9%. Use the practical method. (b) An investment fund guarantees to double your money in 5 years. What rate of interest j2 is implied? (c) If money doubles at a certain rate of interest compounded monthly in 6 years, how long will it take to the same amount of money to triple in value?