To calculate the monthly payments and total cost of financing through both banks, we can use the formula for calculating the monthly payment on an installment loan. The formula is:
\[ PMT = \frac{P \cdot r(1 + r)^n}{(1 + r)^n - 1} \]
Where:
- \(PMT\) = monthly payment
- \(P\) = principal amount (loan amount)
- \(r\) = monthly interest rate (annual interest rate / 12)
- \(n\) = total number of payments (loan term in months)
Step 1: Calculate the monthly payments for both banks.
Bank #1 (BB&T):
- Principal (P) = $20,200
- Annual Interest Rate = 12%
- Monthly Interest Rate (r) = 12% / 12 = 1% = 0.01
- Loan Term = 4 years = 4 * 12 = 48 months (n)
\[ PMT = \frac{20200 \cdot 0.01(1 + 0.01)^{48}}{(1 + 0.01)^{48} - 1} \]
First, calculate \( (1 + 0.01)^{48} \): \[ (1.01)^{48} \approx 1.60844 \]
Now substitute into the PMT formula: \[ PMT = \frac{20200 \cdot 0.01 \cdot 1.60844}{1.60844 - 1} \] \[ PMT = \frac{20200 \cdot 0.0160844}{0.60844} \approx \frac{324.08688}{0.60844} \approx 532.31 \]
Total Cost for Bank #1:
Total Cost = Monthly Payment * Total Number of Payments \[ Total\ Cost = 532.31 \times 48 \approx 25,565.68 \]
Bank #2 (Sunflower):
- Principal (P) = $20,200
- Annual Interest Rate = 9%
- Monthly Interest Rate (r) = 9% / 12 = 0.75% = 0.0075
- Loan Term = 6 years = 6 * 12 = 72 months (n)
\[ PMT = \frac{20200 \cdot 0.0075(1 + 0.0075)^{72}}{(1 + 0.0075)^{72} - 1} \]
First, calculate \( (1 + 0.0075)^{72} \): \[ (1.0075)^{72} \approx 1.747422 \]
Now substitute into the PMT formula: \[ PMT = \frac{20200 \cdot 0.0075 \cdot 1.747422}{1.747422 - 1} \] \[ PMT = \frac{20200 \cdot 0.013105665}{0.747422} \approx \frac{264.752053}{0.747422} \approx 354.07 \]
Total Cost for Bank #2:
Total Cost = Monthly Payment * Total Number of Payments \[ Total\ Cost = 354.07 \times 72 \approx 25,483.04 \]
Summary of Results
| Bank | Monthly Payment | Total Cost of the Car | |----------------|------------------|------------------------| | Bank #1 (BB&T) | $532.31 | $25,565.68 | | Bank #2 (Sunflower) | $354.07 | $25,483.04 |
Best Option
Bank #2 (Sunflower) is the better option as it has both a lower monthly payment and a lower total cost.
Step 2: Determine the cost of paying in full
The total cost of the vehicle, including sales tax.
Assuming a TN state sales tax rate of 7%. \[ \text{Sales Tax} = \text{Car Price} \times \text{Tax Rate} = 20200 \times 0.07 = 1414 \]
Total cost of the car when paying upfront: \[ \text{Total Cost} = \text{Price} + \text{Sales Tax} = 20200 + 1414 = 21614 \]
Step 3: Calculate Savings
Calculate the savings by paying upfront versus financing with the better bank (Bank #2).
\[ \text{Total Cost of Financing} - \text{Total Cost When Paid Upfront} = 25483.04 - 21614 = 3879.04 \]
Conclusion
- Total Cost of Car with Bank #1: $25,565.68
- Total Cost of Car with Bank #2: $25,483.04
- Total Cost of Car if paid upfront: $21,614
- Savings by paying upfront versus financing with the better bank (Bank #2): $3,879.04