Assume that two investments are combined in a portfolio.

a. In words, what is the expected rate of return on the portfolio?

b. What condition must be present for the portfolio to have lower risk than the weighted average of the two investments?

c. Is it possible for the portfolio to have lower risk than that of either investment?

d. Is it possible for the portfolio to be riskless? If so, what condition is necessary to create such a portfolio?