math
posted by twayne .
How long will it take for an investment of $13,000 to double if the investment earns interest at the rate of 6%/year compounded continuously?

13000 e^.06t = 26000
e^.06t = 2
take ln of both sides
ln e^.06t = ln 2
.06t ln e = ln2 , but lne = 1
t = ln2/.06
= appr 11.55