A. 11/1900
B. 44/1900
C. 66/1900
D. 99/1900
A bag contains n white and n black balls. Pairs of balls are drawn at random without replacement successively , until the bag is empty , if the number of ways in which each pair consists of one white and one black ball is 14,400 then n=
Bag A contains 2 red, 3 black balls. Bag B contains 3 red, 2 black balls. One ball is drawn from the bag A and placed in B. One ball is drawn from bag B and placed in A. The probability that the composition of balls in the bags unaltered is
C1+2.C2+3.C3+…….+n.Cn =
A speaks truth in 80%of the cases and B in 60% of the cases. The percentage of the cases of which they likely to contradict each other in stating the same fact is
Four tickets marked 00,01,11 respectively are placed in a bag. A ticket is drawn at random 5 times being replaced each time. The probability that the sum of the numbers on the tickets is 22 is
In each of a set of games it is 2 to 1 in favour of the winner of the previous game. The chance that the player who wins the first game shall win three at least of the next 4 is
Four persons entered the lift cabin on the ground floor f a 7 floor house. Suppose that each of them independently and with equal probability can leave the cabin at any floor beginning with the first. The probability of all 4 persons leaving at different floors is
An urn A contains 3 white and 5 black balls. Another urn B contains 6 white and 8 black balls. A ball is picked from A at random and then transferred to B. Then a ball is picked at random from B. The probability that it is a white ball is :
A, B, Care 3 news papers published from a city.20%of the population read A,16% read B,14% read C, 8% both A and C, 4% B and C,and2% read all the three. The percentage of then population who read at least one paper is
A bag contains 4 tickets numbered 1,2,3,4and another bag contains 6 tickets numbered 2,4,6,7,8,9. One bag is chosen and a ticket is drawn. The probability that the ticket bears the number 4 is