A bag contains 3 black and 2 red balls. One by one 3 balls are drawn from the bag without replacement .
The probability that the third ball is red, is
One Indian and four American men and their wives are to be seated randomly around a circular table. Then the
conditional probability that the Indian man is seated adjacent to his wife given that each American man is seated
adjacent to his wife, is
If in a frequency distribution the mean and median are 21 and 22 respectively, then its mode is approximately
24.0
25.5
20.5
22.0
A key bunch contains 10 keys of which only one key can open a door. A man tries to open the door by choosing a
key at random and discarding the wrong key after each trial. The probability that the door is opened in the fifth trial is
A and B are events such that
A = B
P(A) = P(B)
A and B are independent
All of the above
If 6 objects are distributed at random among 6 persons, the probability that at least one person does not get any object is
Let A and B be two events such that
mutually exclusive and independent
independent but not equally likely
equally likely but not independent
equally likely and mutually exclusive
The marks of some students were listed out of 75. The SD of marks was found to be 9. Subsequently the marks were raised to a maximum of 100 and variance of new marks was calculated. The new variance is
81
122
144
None of these
If 3 numbers are selected from the first 15 natural numbers, then the probability that the numbers are in AP is
A bag contains 7 tickets numbered 0,1,2,...6. Four tickets are drawn one by one with replacement. The probability that
the sum of the numbers on them is 8, is