Question 1007988
We use the formula for continuously compounded interest,
A(t) = Ao * e^(rt)
Plugging in we get
5000 = 2500 * e^(.0618t)
and solve for t
2 = e^(.0618t)
ln 2 = .0618t
t = ln 2 / .0618 = 11.2 years