# problem with compound interest: find doubling time

#### phillipsjr9800

##### New member
I have to complete a table using compound interest.

I know the formual is A=Pe^rt

For this problem I am give the amount after 10 years and the interest rate.
So it should look like this to start 10,000 = Pe^.045t

now I need to find the initial investment and time to double.
This is where I get lost.

Any help would be greatly apprecated.

#### galactus

##### Super Moderator
Staff member
Re: problem with compound interest

The time to double. Then A should be twice P. In this case, P=5000.

Now, solve for t.

$$\displaystyle 10,000=5000e^{.045t}$$

Can you solve for t?.