Consider the three stocks in the following table. Pt represents price at time t, and Qt repr period 8 92 52 104 100 200 200 97 47 114 100 200 200 97 47 57 100 200 400 Calculate the first-period rates of return on the following indexes of the three stocks: (Do places.) a. A market value-weighted index Rate of return b. An equally weighted index Rate of return