(Solution Download) How many variance terms and how many covariance terms do you need to calculate the risk of a...

a. How many variance terms and how many covariance terms do you need to calculate the risk of a 100-share portfolio?
b. Suppose all stocks had a standard deviation of 30 percent and a correlation with each other of .4. What is the standard deviation of the returns on a portfolio that has equal holdings in 50 stocks?
c. What is the standard deviation of a fully diversified portfolio of such stocks?