Why is 0 not an identity for subtraction? explain

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?

How do you find the distance of each number from the mean

What is the area of the shaded sector?