Three boxes, one large, one medium, and one small, contain white
and red balls. The large box, which is chosen half the time,
contains fifteen white balls and eight red ones; the medium box,
which is chosen three times out of ten, contains nine white balls
and three red ones. The small box contains four white balls and
five red ones. (a) On choosing two balls at random from the large
box, what is the probability of (i) getting two...