*please show formulas*

Year A B C Market Index Treasury 2010 19 1196 196 296 196 2011 29% 5% 5% 4% 296 11% -5% -596 1% 296 596 296 11% -3% 2% 2012 2013 2014 2015 -596 196 2% 4% 196 4% 49 4% 5% 1 % 1. Use the above table of returns to answer the following questions: a. Calculate the returns of an equally weighted portfolio of A, B and C b. Calculate the betas of A, B, C and the equally weighted portfolio using the variances and covariances of the returns c. Calculate the betas of A, B, C and the equally weighted portfolio using the variances and covariances of the excess returns d. Do you get the same numbers under a) and b)? Explain