Final answer:
She can afford a maximum loan amount of $2,725,714.29. After 30 years, Joanna will end up paying a total of $4,320,000.
Step-by-step explanation:
To calculate the maximum loan Joanna can afford, we can use the present value formula:
PV = PMT * ((1 - (1 + r)^(-n)) / r)
Where PV is the maximum loan Joanna can afford, PMT is the annual payment she can afford ($12,000), r is the interest rate per period (4.2% divided by 12), and n is the total number of payment periods (30 years multiplied by 12). Plugging in the values, we get:
PV = $12,000 * ((1 - (1 + 0.042/12)^(-30*12)) / (0.042/12))
PV ≈ $12,000 * ((1 - 0.2272) / 0.0035)
PV ≈ $12,000 * (0.7728 / 0.0035)
PV ≈ $2,725,714.29
Therefore, Joanna can afford a maximum loan amount of approximately $2,725,714.29.
To calculate the total amount Joanna will end up paying after 30 years, we can use the formula:
Total Payment = PMT * (n * 12)
Plugging in the values, we get:
Total Payment = $12,000 * (30 * 12)
Total Payment = $4,320,000
Therefore, Joanna will end up paying a total of $4,320,000 after 30 years.