pedro has a balance of $$5810 on a credit card with an APR of 16.2%. paying off his balance in which of these lengths of time will result in him paying the least amount of interest?

13 months
9 months
11 months
7 months

1 answer

To determine which option results in the least amount of interest paid, we can calculate the total interest for each repayment period using the formula for simple interest, which is:

\[ \text{Interest} = \text{Principal} \times \text{Rate} \times \text{Time} \]

Where:

  • Principal is the initial balance
  • Rate is the annual percentage rate (as a decimal)
  • Time is the time period in years

Given:

  • Principal = $5810
  • APR = 16.2% = 0.162

We will calculate the interest for each repayment period in months and convert it into years by dividing by 12.

  1. For 13 months: \[ \text{Time} = \frac{13}{12} \approx 1.0833 \text{ years} \] \[ \text{Interest} = 5810 \times 0.162 \times 1.0833 \approx 1,020.92 \]

  2. For 9 months: \[ \text{Time} = \frac{9}{12} = 0.75 \text{ years} \] \[ \text{Interest} = 5810 \times 0.162 \times 0.75 \approx 706.41 \]

  3. For 11 months: \[ \text{Time} = \frac{11}{12} \approx 0.9167 \text{ years} \] \[ \text{Interest} = 5810 \times 0.162 \times 0.9167 \approx 872.43 \]

  4. For 7 months: \[ \text{Time} = \frac{7}{12} \approx 0.5833 \text{ years} \] \[ \text{Interest} = 5810 \times 0.162 \times 0.5833 \approx 561.05 \]

Now, summarizing the interest paid for each option:

  • 13 months: $1,020.92
  • 9 months: $706.41
  • 11 months: $872.43
  • 7 months: $561.05

From these calculations, the repayment period of 7 months results in the least amount of interest paid at approximately $561.05.