Hello. In a maturity value interest question I am not quite sure what formula to use to get time, and also what measurement I should be using for the time (days, months, etc)

The question is:

Calculate the time period of an investment in a mutual fund that matured to $250,000 yielding an interest of $75,000 at 6% compounded semi-annually? Please round your answer up to the nearest month.What I have done so far:

S = P + I so P=S-I P = 250,000-75,000 = 175,000

Now that I have S, P, and I, time is required.

I tried using t=i/pr which gets me 75,000 / [250,000*0.06] which = 5

Is that 5 years? Another thing is that equation didnt account for the semi annual compounding :s

Thanks