10. What proportion of earnings is being plowed back into the firm if the sustainable growth rate is 8% and the firm's ROE is 20%? a, 60% b, 80% . 20% d. 40% 11. The semi-strong form of the efficient market hypothesis states that a. the efficient market hypothesis is only half true. b. professional investors make superior profits but amateurs can't. c. stock prices do not follow a random walk. d. Stock prices reflect all publicly available information