Suppose that two balanced dice are tossed repeatedly and the sum of the two uppermost faces is determined on each toss. a) What
is the probability that we obtain a sum of 3 before we obtain a sum of 7? Hint: Let A denote the event of a sum of 3. Let B denote the event of no sum of 3 or 7. Now, begin to list the out the sample space in terms of A and B - it should be recognizable in the lecture notes. Hint: A useful infinite series result when |z| < 1: 1 + z + z 2 + z 3 + z 4 + . . . = 1 1 − z
