4-7. What is the present value (PV) of an investment that will pay $2,500 in five years if the opportunity cost rate is 9 percent compounded (a) annually. (b) quarterly, and (c) monthly? Explain why the PV is lowest when interest is compounded monthly 4-10. At the end of each of the past 14 years, Vanessa deposited $450 in an account that earned 8 percent compounded annually. (a) How much is in the account today? (b) How much would be in the account if the deposits were made at the beginning each year rather than at the end of each year? 4-12 Suppose your opportunity cost rate is 11 percent compounded annually. (a) How much must you deposit in an account today if you want to pay yourself $230 at the end of each of the next 15 years? (b) How much must you deposit if you want to pay yourself $230 at the beginning of each of the next 15 years: 4-18 Ten years ago, Bruce invested $1,250. Today, the investment is worth $3,550. If interest is compounded annually, what annual rate of return did Bruce earn on his investment? 4-24 When Sarah Jean purchased her house 12 years ago, she took out a 30-year mortgage for $220,000. The mortgage has a fixed interest rate of 6 percent compounded monthly. (a) Compute Sarah Jean's monthly mortgage payments. (b) If Sarah Jean wants to pay off her mortgage today, for how much should she write a check? She made her most recent mortgage payment earlier today