please include formulas and steps:

B5. (CAPM) What is the beta of a stock when its expected return is 15%, its standard deviation of return is 25%, its correlation coefficient with the market is 0.2, and the return to the market portfolio is 14% with a standard deviation of 4%? Assuming the market for this stock is in equilibrium, what is the riskless return that is implied by the information given? (cam) TILL 2.11