Four numbers are chosen at random from{1, 2, 3, ..., 40}. The probability that they are not consecutive, is
If A and B are mutually exclusive events with P(B) 1, then P(A) is equal to(Here is the complement of the event B)
D.
Seven white balls and three black balls are randomly arranged in a row. The probability that no two black balls are placed adjacently is
A student has to answer 10 out of 13 questions in an examination choosing atleast 5 questions from the first 6 questions. The number of choice available to the student is
63
91
161
196
A candidate takes three tests in succession and the probability of passing the first test is p. The probability of passing each succeeding test is p or according as he passes or fails in the preceding one. The candidate is selected, if he passes atleast two tests. The probability that the candidate is selected, is
p2(2 - p)
p(2 - p)
p + p2 + p3
p2(1 - p)
Two persons A and B are throwing an unbiased six faced dice alternatively, with the condition that the person who throws 3 first wins the game. If A starts the game, then probabilities of A and B to win the same are, respectively
3 out of 6 vertices of a regular hexagon are chosen at a time at random. The probability that the triangle formed with these three vertices is an equilateral triangle, is
A bag P contains 5 white marbles and 3 black marbles. Four marbles are drawn at random from P and are put in an empty bag Q. If a marble drawn at random from Q is found to be black then the probability that all the three black marbles in P are transfered to the bag Q
There are 10 intermediate stations on a railway line between two particular stations. The number ofways that a train can be made to stop at 3 of these intermediate stations so that no two of these halting stations are consecutive is
56
20
126
120
If 12 identical balls are to be placed in 3 identical boxes, then the probability that one of the boxes contains exactly 3 balls, is