Two bags, A and B, each contain balls which are either red or yellow or green. Bag A contains 4 red, 3 yellow and :1 green balls. Bag B contains 5 red, 3 yellow and 1 green ball. A ball is selected at random 'om bag A and placed into bag B. A ball is then selected at random from bag B and placed into bag A. The probability that bag A now contains an equal number of red, yellow and green balls is p. Given that p > 0, nd the possible values of n and p. (5}