A stock has a beta of 1.3 and an expected return of 12.8 percent. A risk-free asset currently earns 4.3 percent. a. What is the expected return on a portfolio that is equally invested in the two assets? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) b. If a portfolio of the two assets has a beta of 90 , what are the portfolio weights? (Do not round intermediate calculations and round your answers to 4 decimal places, e.g., 1616.) c. If a portfolio of the two assets has an expected return of 12 percent, what is its beta? (Do not round intermediate calculations and round your answer to 2 decimal places, e.g., 32.16.) d. If a portfolio of the two assets has a beta of 2.5, what are the portfolio weights? (A) negative answer should be indicated by a minus sign. Do not round intermediate calculations and round your answers to 4 decimal places, e.g., 1616.)