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 a VISA card, and 11 percent carry both cards. What percentage of its customers carry a credit card that the establishment will accept?

The answer is: 74% of its customers carry a credit card the store will accept.

Explanation:

Let A denote the event a customer carries American Express credit card (24%) Let V denote the event a customer carries Visa credit card (61%) Let AV denote the event a customer carries both credit cards (11%)

P (A ∪ V) = probability that a customer carries at least one credit card

P (A ∪ V) = P (A) + P (V) - P (AV)

P (A ∪ V) = 0.24 + 0.61 - 0.11 = 0.74