28. Exactly four years ago, you purchased shares in a mutual fund for $500. All the dividends were reinvested in the fund, the current value of the shares you own, including those obtained from dividend reinvestment, is $705.80. The dividends paid and reinvested are shown below. Year 2016 2017 2018 2019 Dividend $30 $32 $36 $40 What is your pretax rate of return to date? 29. In problem 17 above, Sarah Truman is concerned that 8% might not be the correct interest rate to use. Sarah would like to know what the rate of interest would have to be to make the two suits of equivalent present value. Sarah plans to make 50 cold water divers per year for the next 6 years. 30. Your father has asked your advice on the following problem. He has a mortgage loan on the family home that was made several years ago when interest rates were lower. The loan has a current balance of $40,000 and will be paid off in twenty years by paying $330 per month. He has discussed paying off the loan ahead of schedule with an officer of the bank holding the mortgage. The bank is willing to accept $36,000 right now to pay it off completely. What interest rate would your father earn by paying off the loan right now rather than making monthly payments for twenty years? Your father is currently earning 9 percent in his investments. Would it be worthwhile paying off the loan if he has the money available