Suppose that $2000 are borrowed at an interest rate of 15%, compounded monthly. If we assume that no payments were made, find the amount due
after 8 years. Don't round the intermediate calculations and round the answer to the nearest penny.



Answer :

To find the amount due after 8 years under compound interest, we can use the compound interest formula: \[ A = P \left(1 + \frac{r}{n}\right)^{nt} \] Where: - \( A \) is the amount of money accumulated after n years, including interest. - \( P \) is the principal amount (the initial amount of money). - \( r \) is the annual interest rate (in decimal form). - \( n \) is the number of times that interest is compounded per year. - \( t \) is the time in years. Let's plug in the values for this problem: - The principal \( P \) is $2000. - The annual interest rate \( r \) is 15%, which as a decimal is 0.15. - The interest is compounded monthly, so \( n \) is 12. - The time \( t \) is 8 years. Now apply these values to the formula: \[ A = 2000 \left(1 + \frac{0.15}{12}\right)^{12 \times 8} \] We can calculate the interest rate per compounding period by dividing the annual interest rate by the number of compounding periods per year: \[ \frac{0.15}{12} = 0.0125 \] Now calculate the exponent by multiplying the number of years by the number of compounding periods per year: \[ 12 \times 8 = 96 \] Substitute these numbers into the compound interest formula: \[ A = 2000 \left(1 + 0.0125\right)^{96} \] \[ A = 2000 \left(1.0125\right)^{96} \] To find out the numerical value of \( A \), we need to calculate \( (1.0125)^{96} \). To do this without rounding intermediate calculations, you can use a calculator: \[ (1.0125)^{96} \approx 3.387417943 \] (without rounding the intermediate calculation) Now multiply this by the principal: \[ A = 2000 \times 3.387417943 \] \[ A \approx 6774.835886 \] Now round off the amount to the nearest penny: \[ A \approx \$6774.84 \] So, after 8 years, with a 15% annual interest rate compounded monthly and no payments made, the amount due would be approximately $6774.84.