The grades on a history midterm at Almond are roughly symmetric with \mu = 85μ=85mu, equals, 85 and \sigma = 2.0σ=2.0sigma, equals, 2, point, 0. Michael scored 868686 on the exam. Find the z-score for Michael's exam grade. Round to two decimal places.

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?