please explain how to find Variance

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 20 percent each in A and B and 60 percent in C ? (Do not round intermediate calculations and round your answer to 6 decimal places, e.g., 32.161616.)