Question

How long it will take for $300 to double when invested at 6% annual interest compounded twice a year?

Answer 1

6% compounded twice a year would be 3% every 6 months.
so after one year you will have $\(300*1.03^2\)
after 'n' years you will have $\(300*1.03^{2n}\)
which means you need to solve:\[300*1.03^{2n}=600\]
do you know how to solve it from here?

Answer 2

2n=ln 2/ln1.03

Answer 3

23 years approx