12. A portfolio has a Macaulay duration of 15.8368 years and have the following assets all yielding at an annual effective rate of 5%: (a) one 10-year annuity immediate with level payment X; (b) one perpetuity immediate with level payment 0.8X; (c) one 30-year $1,000 par value bond with annual coupon rate of 5%. Calculate X. 12. A portfolio has a Macaulay duration of 15.8368 years and have the following assets all yielding at an annual effective rate of 5%: (a) one 10-year annuity immediate with level payment X; (b) one perpetuity immediate with level payment 0.8X; (c) one 30-year $1,000 par value bond with annual coupon rate of 5%. Calculate X