Please show all working and formulas used, thanks!

7. You are considering investing your savings into a share portfolio. You have identified the following shares as suitable candidates for investment: Share A Ltd B Ltd C Ltd Expected Return 6% 9% 15% Beta (B) 0.8 1.0 1.2 a. What is the expected return for a portfolio that has an equal weighting of each company's shares? (2 marks) b. What is the Beta of a portfolio that has an equal weighting of each company's shares? (2 marks)