When three standard dice are tossed, the numbers a,b,c are obtained. Find the probability that (a-1)(b-1)(c-1) not equal to 0
209/207 is sadly wrong...
For the product not to equal 0, each of the three dice must not be a 1.
So, the probability that a isn't a 1 is 5/6
the probability that b isn't a 1 is 5/6
and the probability that c isn't a 1 is 5/6.
Since these are independent, the final probability is 5/6 x 5/6 x 5/6 = 125/216.