Final answer:
To earn $20,000 per year from her investments, the retired woman should invest approximately $184,614.16 in the safe fund and $15,385.84 in the riskier fund.
Step-by-step explanation:
To determine how much the retired woman should invest in each fund, we can set up a system of equations. Let's assume she invests $x in the safe fund and $y in the riskier fund. The total investment is $200,000, so x + y = 200,000. She also wants to earn $20,000 per year from her investments, so 0.09x + 0.13y = 20,000. Solving these equations, we can find the values of x and y:
x + y = 200,000
0.09x + 0.13y = 20,000
Multiplying the second equation by 100 to eliminate decimals, we get:
9x + 13y = 2,000,000
Multiplying the first equation by 9 and subtracting it from the second equation eliminates x, giving us:
13y - 9x = 2,000,000 - 9(200,000) = 2,000,000 - 1,800,000 = 200,000
Now, we can solve this equation for y:
13y = 200,000
y = 200,000 / 13 = 15,385.84
Substituting the value of y back into the first equation, we can solve for x:
x + 15,385.84 = 200,000
x = 200,000 - 15,385.84 = 184,614.16
Therefore, she should invest approximately $184,614.16 in the safe fund and $15,385.84 in the riskier fund to earn $20,000 per year from her investments.