Answer:
7 years
Explanation:
An initial investment of $200 is now valued at $350.
The annual interest rate is 8% compounded continuously.
Formula:

Where,
A is amount, A=350
P is principle, P=200
R is rate of interest, r=0.08
t is time, t=?
Substitute the value into formula


Taking ln both sides


Hence, 7 years ago money was invested.