math probability
posted by Bec on .
you roll 2 dice. what is the probability that at least one of them is a 6.

Let A denote the event that one specific die is a 6.
Let B denote the event that the other die is a 6.
P(A) = 1/6
P(B) = 1/6
Note that the events are independent.
.: P(A˄B)=P(A)P(B)
So we need to find: P(A˅B)
Use the exclusion principle:
P(A˅B) = P(A) + P(B)  P(A˄B)