Suppose CAPM works, and you know that the expected returns on Walmart and Amazon

Suppose CAPM works, and you know that the expected returns on Walmart and Amazon are estimated to be 12% and 10%, respectively. You have just calculated extremely reliable estimates of the betas of Walmart and Amazon to be 1.30 and 0.90, respectively. Given this data, what is a reasonable estimate of the risk-free rate (the return on a long-term government bond)? (Enter the answer with no more nor less than two decimal places, and leave off the % sign. For example, if your answer is 13.97% you should enter it as 13.97 NOT 0.14 nor 14)