申論題

4.(15%) Given a bag having 4 white balls and 3 red balls, let us proceed a drawing run that a drawing

takes a ball from the bag, record its color, put it back, and do such drawing for 5 times. Assume that

the probability of each distinct red ball being drawn is two times of that of a distinct white ball

being drawn. Calculate the probability to draw exactly 3 white balls and 2 red balls in the run.