Little Johnny’s parents have a menagerie consisting of 50% d…

Little Johnny’s parents have a menagerie consisting of 50% dogs, 40% cats, and 10% venomous snakes. They know from experience that 10% of the dogs bite, 5% of the cats bite, and 20% of the snakes bite. Given that little Johnny has been bitten, what is the probability it was a venomous snake?

A representative from the National Football League’s Marketi…

A representative from the National Football League’s Marketing Division randomly selects people on a random street in Kansas City, Kansas until he finds a person who attended the last home football game. Let the probability that he succeeds in finding such a person, equal 0.25. And, let X denote the number of people he selects until he finds his first success. What is the probability that the marketing representative must select 4 people before he finds one who attended the last home football game? What is the probability that the marketing representative must select more than 6 people before he finds one who attended the last home football game?