7. XYZ stock price and dividend history are as follows: An investor buys three shares of XYZ at the beginning of 2018, buys another two shares at the beginning of 2019 , sells one share at the beginning of 2020 , and sells all four remaining shares at the beginning of 2021. (LO 5-1) a. What are the arithmetic and geometric average time-weighted rates of return for the investor? b. What is the dollar-weighted rate of return? (Hint: Carefully prepare a chart of cash flows for the four dates corresponding to the turns of the year for January 1,2018 , to January 1,2021 . If your calculator cannot calculate internal rate of return, you will have to use a spreadsheet or trial and error.)