Calculate the required rate of return for Mars Inc.'s stock. The Mars's beta is 2.0 , the rate on a T-bill is 4 percent, the rate on a long-term T-bond is 5.2 percent, the expected return on the market is 11.5 percent, the market has averaged a 14 percent annual return over the last six years, and Mars has averaged a 14.4 return over the last six years. (Do not include the % sign and round to two decimal places, i.e., 18.31