Three distinct numbers are selected at random from the set {1,2,3,4,5,6}. What is the probability that their product is divisible by 3?

The total number of combinations of 3 from 6 = 6C3 = 20

All possible combinations of 3 which have a product divisible by 3 must contain either a 3 or a 6.

So the number not divisible must be 3 combinations from the number 1, 2, 4 and 5. = which is 4

So the required probability is 20-4? 20 = 16/20 = 0.8 Answer