Please show the formulas you used to get your answer, no excel. Thank You!!!

Stock Y has a beta of 1.6 and an expected return of 16.6 percent. Stock Z has a beta of .8 and an expected return of 9.4 percent. What would the risk-free rate have to be for the two stocks to be correctly priced? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) Risk-free rate 2.20%