# Math Help - Compounded continuously

1. ## Compounded continuously

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.

$A=Pe^{rt}$

I know I am looking for t in the formula. What do I do?

2. Step 1:

Find out what you have

$A = 6200 = 2(3100)$

$P = 3100$

$r = 7\% = .07$

$t = ?$

Step 2:

Fill in what you know

$A = Pe^{rt}$

$6200 = 3100e^{.07t}$

Step 3:

Solve for unknown

$6200 = 3100e^{.07t}$

$2 = e^{.07t}$

$ln(2) = .07t$

$\frac{ln(2)}{.07} = t$

Put that in your calculator and you're done.