At a grocery store, there is a 62% chance that a customer will pay with a credit card and a 25% chance that a customer will pay with cash. What is the probability that a randomly selected customer will pay with a credit card or with cash

Angelo chooses a number from 1 to 10. What is the probability that he chooses an odd number or a multiple of 5

Question

At a grocery store, there is a 62% chance that a customer will pay with a credit card and a 25% chance that a customer will pay with cash. What is the probability that a randomly selected customer will pay with a credit card or with cash

Angelo chooses a number from 1 to 10. What is the probability that he chooses an odd number or a multiple of 5

mathmale · Answer

One customer's behavior will have little or no effect on another customer's behavior, so we can assume that the event A, Customer pays with a credit card, is independent of event B, Customer pays with cash, and that no customer is going to pay with both credit card AND cash.  Thus, the two events a re "mutually exclusive;" we assume they're NOT going tot happen at the same time.

With that said, and seeing that we need to find P(A OR B), which probability formula should we be using, the Addition formula or the Multiplication formula?  You might want to look those up to get a better idea of which one applies here and what to do with the P(A AND B) term that shows up in the correct formula.

mathmale · Answer

In regard to your second question:  Would you please post it as a separate question.  Just copy and paste it into the "Ask a question" box.  Thanks.