11.One hundred identical coins, each with probability p, of showing up a head, are tossed. If 0 < p < 1 and if the probability of heads on exactly 50 coins is equal to that of heads on exactly 51coins then the value of p, is

12.Three faces of a fair die are yellow, two faces red and one blue. The die is tossed 3 times. The probability that the colours yellow, red and blue appear in the first, second and third tosses respectively, is

13.The mean and variance of a binomial variate X are 2 and 1 respectively. The probability that X takes a value greater than 1 is

14.In a box, there are 2 red, 3 black and 4 white alls. Out of these three balls are drawn together. The probability of these being of same colour is

15.The probability that the three cards drawn from a pack of 52 cards are all red is