Find out how long it takes a $3100 investment to double if it is invested at 7% compounded continuously. Round your answer to the nearest tenth of a year.
$\displaystyle A=Pe^{rt}$
I know I am looking for t in the formula. What do I do?
Find out how long it takes a $3100 investment to double if it is invested at 7% compounded continuously. Round your answer to the nearest tenth of a year.
$\displaystyle A=Pe^{rt}$
I know I am looking for t in the formula. What do I do?
Step 1:
Find out what you have
$\displaystyle A = 6200 = 2(3100)$
$\displaystyle P = 3100$
$\displaystyle r = 7\% = .07$
$\displaystyle t = ?$
Step 2:
Fill in what you know
$\displaystyle A = Pe^{rt}$
$\displaystyle 6200 = 3100e^{.07t}$
Step 3:
Solve for unknown
$\displaystyle 6200 = 3100e^{.07t}$
$\displaystyle 2 = e^{.07t}$
$\displaystyle ln(2) = .07t$
$\displaystyle \frac{ln(2)}{.07} = t$
Put that in your calculator and you're done.