I'm having trouble finding the formula appropriate for the following question.

Calculate the beta of the portfolio and use the Capital Asset Pricing Model (CAPM) to compute the expected rate of return for the portfolio. Assume that the expected rate of return on the market is 16 percent and that the risk-free rate is 8 percent.

Stock A: $224,000 1.50 Beta

Stock B: $336,000 0.69 Beta

Stock C: $560,000 1.35 Betta