Using dollar-cost averaging will help you reduce your risk over

Using dollar-cost averaging will help you reduce your risk over time by ensuring that you do not try to time the market. An investor regularly contributes $20 000 to his DRIP account for five years. The share price fluctuates over time as follows:
Using dollar-cost averaging will help you reduce your risk over

(a) Calculate the investor€™s average cost per share.
(b) Calculate the value of the investment after five years.
(c) Calculate the yield of the investments.