Please show steps with excel if possible. Please include the equations so I can learn it. Thank you!

Consider the following information: a. What is the expected return on an equally weighted portfolio of these three stocks? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) b. What is the variance of a portfolio invested 25 percent each in A and B and 50 percent in C? (Do not round intermediate calculations and round your answer to 5 decimal places, e.g., 32.16161.) Answer is complete but not entirely correct