This is a continuous growth problem So use the formula y= A e^kt where y is final value a is initial value k is growth factor a t is time
First we have to solve for k
If the population triples in 6 months then y/a =3 and t= 6
3= e^6k
ln3 =ln e^6k
ln 3 = 6k k = (ln3)/6 k=.1831 We can use this now to get time it takes to double. In this case y/a=2
2= e^.1831t
ln 2 = ln e^.1831t
ln 2 = .1831 t t= (ln2)/.1831 t= 3.7856 months