# Three dice rolled

Three indistinguishable (fair) dice are thrown simultaneously at random. Find the probability that the sum of the three dice is less than six and that no two dice show the same face (the same number).

I know that the probability that the sum three dice is less than six is 10/216 (or 5/108) and the probability that no two dice show the same face is 5/9. I don't know how to put them all together?!

• It may be helpful to know that $P(A\cap B)=P(A|B)P(B)$. Hint let $A=$ sum of faces is less than six and $B=$ no two dice have same face Commented Sep 22, 2014 at 3:00
• Yes, I know the formula P(A|B) = P(A∩B)/P(B). But I don't know P(A∩B) Commented Sep 22, 2014 at 3:03
• You don't need to know $P(A \cap B)$, that's what you're finding out. You can quite easily calculate $P(A \mid B)$, however. Commented Sep 22, 2014 at 3:05
• Exactly, is it quite simple to calculate prob for no same faces. Then given that its easy to calculate prob sum of faces is less than 6 Commented Sep 22, 2014 at 3:07