Need some help with the P(A intersect B) portion of the screen shot How do you calculate the 1/6 I{4,6}| ? In other words how did they get 2/6? And what does the triangle mean?

SC CLIOII Of A and b ( Which is itself an event in s ), that is, the set Of all states of the world in which both A and B occur. We illustrate this point with the following example. Example 1.1.6. A Fair Die Roll Consider a roll of one fair (six-sided) die. Let S = {1, 2, 3, 4, 5,6), S = P(S) (the power set-that is, the set of all subsets-of S), and P(A) = = |AI, VA ES. Let A = {w E n : w> 4) = (4,5,6) and B = (we S : w is even} = (2, 4, 6). Then P(AnB) = P( 14, 5,6) n (2, 4,6)) = P( 14, 6) ) = 14 , 6} = ON Just as P(An B) is the probability that both A and B will occur in a single draw from (S, S, P), P(AUB) is the probability that A or B (or both) will occur in a single draw from (S, S, P). The following theorem allows us to relate these two probabilities