A and B are two events. If A and B are independent, then the probability that events A and B both occur is:

p(A and B) = p(A) x p(B).

In other words, the probability of A and B both occurring is the product of the probability of A and the probability of B.

What is the probability that a fair coin will come up with heads twice in a row? Two events must occur: a head on the first toss and a head on the second toss. Since the probability of each event is 1/2, the probability of both events is: 1/2 x 1/2 = 1/4.

Now consider a similar problem: Someone draws a card at random out of a deck,