2. A pair of dice is rolled until a sum of either 5 or 7 appears. Find the probability first. (Hint. Let En denote the event that a 5 occurs on the nth roll and no 5 or 7 occurs on the first n - 1 rolls.) 3. A retail establishment accepts either the American Express or the VISA credit card. A total of 24 percent of its customers carry an American Express card, 61 percent carry VISA card, and 11 percent carry both cards. What percentage of its customers carry a credit card that the