The correct answer is 10, please show how to derive it.

Suppose that 16 risky assets have been identified whose rates of return satisfy ri= ta+ f + ; where a > 0. Note that 8 of the risky assets use the + sign in front of a in the equation, while the other 8 use the sign. The factor f is common to all 16 risky assets. The factor f has a mean of 10 and standard deviation equal to 3. Each , represents a specific error, in the sense that each has zero mean, zero covariance with f. and zero covariance with the other risky assets. Each e; has a standard deviation equal to 4. Now assume that a portfolio consists of all of these stocks, with equal weight given to each one of them. What is the expected rate of return of the portfolio? Please express your answer in numerical form, and round your numerical answer to the nearest integer. Suppose that 16 risky assets have been identified whose rates of return satisfy ri= ta+ f + ; where a > 0. Note that 8 of the risky assets use the + sign in front of a in the equation, while the other 8 use the sign. The factor f is common to all 16 risky assets. The factor f has a mean of 10 and standard deviation equal to 3. Each , represents a specific error, in the sense that each has zero mean, zero covariance with f. and zero covariance with the other risky assets. Each e; has a standard deviation equal to 4. Now assume that a portfolio consists of all of these stocks, with equal weight given to each one of them. What is the expected rate of return of the portfolio? Please express your answer in numerical form, and round your numerical answer to the nearest integer