A manager buys three shares of stock today, and then sells one of those shares each year for the next 3 years. His actions and the price history of the stock are summarized below. The stock pays no dividends. Time 0 1 2 3 Price $ 180 200 200 200 Action Buy 3 shares Sell l share Sell l share Sell l share a. Calculate the time-weighted geometric average return on this "portfolio." (Do not round intermediate calculations. Round your answer to 2 decimal places.) Geometric average return % b. Calculate the time-weighted arithmetic average return on this portfolio. (Do not round intermediate calculations. Round your answer to 2 decimal places.) Arithmetic average return %