First, start of by saying what the probability of getting a 4 is, which is 1/6.
Now, this means the probability of not getting a 4 is 1-(1/6)=(5/6), since the total probability is 1.
After doing this, you should think about what it means to only get 4 on the last trial, the 4th trial. It means that the probabilities of the 1st, 2nd, and 3rd trial were (5/6) each. The 4th trial had a probability of (1/6). So the probability would be calculated as following: ([tex](5/6)^3*(1/6)[/tex]=[tex]5^3/6^4[/tex]. You can use a calculator or your computer to find out that the probability is 125/1296.
I hope this was helpful!
