Answer:
Explanation:
To determine how long Justin should borrow the money, we can use the formula for calculating the number of periods (or months) needed to repay a loan:
n = (log(PMT) - log(PMT - (PV × i))) / log(1 + i)
Where:
n = number of periods (in months)
PMT = monthly payment ($400)
PV = present value (loan amount, $19,864)
i = monthly interest rate (APR divided by 12 months and 100)
Let's calculate it step by step:
1. Convert the annual interest rate to a monthly rate:
i = 9% / 12 / 100 = 0.0075
2. Substitute the values into the formula:
n = (log(400) - log(400 - (19864 × 0.0075))) / log(1 + 0.0075)
3. Use a calculator to evaluate the expression inside the logarithms:
n ≈ (log(400) - log(400 - 148.98)) / log(1.0075)
4. Simplify the expression inside the logarithms:
n ≈ (2.602 - 2.575) / 0.001318
5. Evaluate the remaining expression:
n ≈ 0.027 / 0.001318
6. Calculate the final result:
n ≈ 20.5
Therefore, Justin should borrow the money for approximately 20.5 months in order to afford his monthly payment of $400.
Rounding to the nearest tenth of a year, Justin should borrow the money for approximately 20.5 / 12 = 1.7 years.