hey please can i get a detail explanation please, not just a screenshot of excel

3-For the three problems (a, b, and c) below: (2 Points) Consider historical data showing that the average annual rate of return on the S\&P 500 portfolio over the past 90 years has averaged roughly 8% more than the Treasury bill return, and that the S\&P 500 standard deviation has been about 20% per year. Assume these values are representative of investors' expectations for future performance and that the current T-bill rate is 5%. a. Calculate the expected return and variance of portfolios invested in T-bills and the S\&P 500 index with weights as follows: b. Calculate the utility levels of each portfolio of Problem a for an investor with A=2. What do you conclude? c. Repeat Problem b for an investor with A=3. What do you conclude