Question

Yet another question.

Answer 1

t= 3 years

Explanation:

So far we have 2 useful relationships
`P_(t)= P_(o) e^(r*t)` and
`P_(t)=2P_(0)`

Now, clearing t

`P_(t)= P_(o) e^(r*t) \\( P_(t))/(P_(o)) = e^(r*t)\\(2 P_(0))/(P_(o)) = e^(r*t)\\2 = e^(r*t)`

I apply logarithm

`log(2)=r*t\\ t=(log(2))/(r)\\t=(0.3)/(0.1) \\ t=3` years

Done