Answer:
optimal solution is 0.6B + 0.4S
highest possible yield = 13.4%
Explanation:
we have to maximize 0.09B + 0.2S
where:
B = amount invested in bonds
S = amount invested in stocks
constraints:
B ≥ 0.6
B + S = 1
S ≥ 0
0.09B + 0.2S ≥ 0.085
using solver, the optimal solution is 0.6B + 0.4S
the portfolio's yield = (0.6 x 0.09) + (0.4 x 0.2) = 5.4% + 8% = 13.4%