A. 1/6
B. 1/3
C. 1/2
D. none
A bag consists a white and b black balls. Two players A and B alternatively draw a ball from the bag, replacing the ball each time after the draw till one of them draws a white ball and wins the game. A begins the game. If the probability of A winning the game is three times that of B, then a:b=
There are 5 letters and 5 addressed envelopes. If the letters are put at random in the envelopes, the probability that at least one letter may be placed in wrongly addressed envelope is
India plays two matches each with west indies and Australia. In any match the probabilities of India getting points 0,1 and 2 are 0.45,0.05 and 0.50 respectively. Assuming that the outcomes are independent, the probability of getting at least 7points is
A student appears for test I,II and III. The student is successful if he passes either in tests I and II or III. The students passing in tests I,II and III are p, q and 1/2respectively.Ifthe probability that the student is successful is 1/2 then
3 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 second and third tosses respectively is
100 tickets are numbered as 00,01, 02,...,09,10,11,...99. When a ticket is drawn at random from them and if B is the event of getting 0 as the product of the numbers on the ticket, then P(B)=
I. In a class 25% of thestudents failed in mathematics, 30% failed in chemistry and 15% failed in both Mathematics and chemistry. If a student is selected at random failed in Mathematics, the probability that he failed in chemistry is 1/2
II: A bag contain 10 identical balls of which 4 are blue and 6 are red. 3 balls are taken out at random from the bag one after the other. The probability that all the 3 balls drawn are red is 1/6
If 2 numbers are randomly selected from 20 consecutive natural numbers, then the probability that the sum of the two numbers is an even number is
5 boys and 3 girls sit in a row at random. If a is the probability that all the girls sit together, b is the probability that all the boys sit together and c is the probability that all the boys and all the girls sit together then the ascending order a,b,c is
For a student the probability of getting a pass in one paper is75%and the probability of getting a pass in another paperis60%.The probability is 60% .The probability for the student to pass in one paper only is