Final answer:
To calculate how many years before Luxury Challenged runs out of money, subtract the income from living expenses and divide the total investment by the annual shortfall.
Step-by-step explanation:
To find out how many years before Luxury Challenged runs out of money, we need to calculate the annual shortfall and divide it by the annual withdrawal from the municipal-bond mutual fund.
The annual shortfall is calculated by subtracting the monthly pension and Social Security income from the monthly living expenses and multiplying the result by 12. In this case, the annual shortfall is ($16,600 - $9,100 - $3,100) x 12 = $54,000.
Then, we divide the total amount invested in the mutual fund by the annual shortfall. In this case, $820,000 / $54,000 = 15.19 years.
Therefore, Luxury Challenged will run out of money in approximately 15 years.