Investor wants to invest 30,000 in corporate bonds that are rated AAA, a, and B. Lower rated bonds pay higher interest, but pose a higher risk as well. The average yield is 5% on AAA bonds, 6% on A bonds, and 10% on B bonds. How much should they invest in each type of bond to have an interest income of $2000? Give a general solution stating any limitations on the parameter. Then provide two specific solutions and compare. Is one of those two solutions preferable over the other? If so, why might that be the case? If not, why are the two specific solutions equally preferable?