\( \$ 1000 \) were deposited into an account with a \( 7 \% \) interest rate, compounded continuously. How many years was it in the bank if the current amount is \( \$ 2500 \) ? \[ \mathrm{t}=[\text { ? ] years } \]
Real Tutor Solution
Answer
Solution
Reviewed and approved by the UpStudy tutoring team
Mind Expander
To find out how many years the money was in the bank, we can use the formula for continuous compounding, which is given by: \[ A = Pe^{rt} \] Where: - \( A \) is the amount of money accumulated after time \( t \), - \( P \) is the principal amount (the initial deposit or investment), - \( r \) is the annual interest rate (decimal), - \( e \) is the base of the natural logarithm (approximately equal to 2.71828), - \( t \) is the number of years the money is invested or borrowed for. Plugging in the given values into the formula we have: \[ 2500 = 1000 e^{0.07t} \] Dividing both sides by 1000: \[ 2.5 = e^{0.07t} \] Now we take the natural logarithm (ln) of both sides: \[ \ln(2.5) = 0.07t \] Now, solve for \( t \): \[ t = \frac{\ln(2.5)}{0.07} \] Calculating \( \ln(2.5) \): \[ \ln(2.5) \approx 0.9163 \] Now, substituting back: \[ t = \frac{0.9163}{0.07} \approx 13.09 \] Therefore, the money was in the bank for approximately \( 13.09 \) years. \[ \mathrm{t} \approx 13.1 \text{ years} \]