A Mexican restaurant sells quesadillas in two sizes: a "large" 12 inch-round quesadilla and a "small" 5 inch-round quesadilla. Which is larger, half of the 12−inch quesadilla or the entire 5−inch quesadilla?

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?