An investment firm recommends that a client invest in bonds rated aaa, a, and b. the average yield on aaa bonds is 5%, on a bonds 7%, and on b bonds 12%. the client wants to invest twice as much in aaa bonds as in b bonds. how much should be invested in each type of bond under the following conditions? a. the total investment is $28 comma 000, and the investor wants an annual return of $2 comma 020 on the three investments. b. the values in part a are changed to $35 comma 000 and $2 comma 530, respectively.

You are the manager of a large crude-oil refinery. as part of the refining process, a certain heat exchanger (operated at high temperatures and with abrasive material flowing through it) must be replaced every year. the replacement and downtime cost in the first year is $165 comma 000. this cost is expected to increase due to inflation at a rate of 7% per year for six years (i. e. until the eoy 7), at which time this particular heat exchanger will no longer be needed. if the company's cost of capital is 15% per year, how much could you afford to spend for a higher quality heat exchanger so that these annual replacement and downtime costs could be eliminated?