Help with story problem?

mathmathmath:

the problem is:

Find the time required for money invested at an annual rate of 4% to double in value if the investment is compounded continuously. Round to the nearest hundredth of a year.

please help

You have to give the initial amount of money a value. It doesn't matter how much because $5 will double in the same amount of time as$1000 will double.
I'm going to start with $1 because it is easiest and I need to work out how long it will be before I have$2.

Inially I have $1 After one year I have$1*1.04 = 1.04 (dollars)
After 2 years I have 1.04*1.04 = 1.04 ²
After 3 years I have 1.04 ²*1.04 = 1.04 ³

After n years I have 1.04 ⁿ dollars
The answer will be given by the equation

2=1.04 ⁿ
Since it is the exponent that you need to find, you wil need to take the log of both sides to get the answer.

Try to finish it by yourself.