don't answer unless you actually know how to do it, please

3. Answer the following independent questions: a) Scheduled payments of $7000 due now and $7000 due in four years are to be replaced by a payment of $7000 due in two years and a second payment due in seven years. Determine the size of the second payment if interest is 10.5% compounded annually and the focal date is seven years from now. b) An investment in a lease offers returns of $2500 per month due at the beginning of each month for five years. What investment is justified if the returns are deferred for two years and the interest required is 12% compounded monthly