Probability Theory on random selection.

          There are two boxes, containing 1 black ball and 10 white balls and 6 black balls and 7 white balls respectively. 4 Balls are randomly taken from the first box and put in the second box. Then one ball is drawn out from the second. Find the probability that: 1) the ball is white 2) only white balls were taken from the first box and the ball taken from the second box is black