A father has 3 children with at least one boy. The probability that he has 2 boys and 1 girl is a. `1//4` b. `1//3` c. `2//3` d. none of these

A four figure number is formed of the figures 1, 2, 3, 4, 5 with no repetitions. The probability that the number is divisible by 5 is 3//4 b. 1//4 c. 1//8 d. none of these

A man alternately tosses a coin and throws a die beginning with the coin. The probability that he gets a head in the coin before he gets a 5 or 6 in the dice is 3//4 b. 1//2 c. 1//3 d. none of these

6 boys and 6 girls sit in row at random. the probability that all the girls sit together is a. 1/(432) b. (12)/(431) c. 1/(132) d. none of these

2n boys are randomly divided into two subgroups containint n boys each. The probability that the two tallest boys are in different groups is a. n//(2n-1) b. (n-1)//(2n-1) c. (n-1)//4n^2 d. none of these

In a family, out of 3 children, one of them at least Boy. Find the porbability of two boys in this family.

The sum of two positive quantities is equal to 2ndot the probability that their product is not less than 3/4 times their greatest product is a. 3//4 b. 1//4 c. 1//2 d. none of these

The number of possible outcomes in a throw of n ordinary dice in which at least one of the die shows and odd number is a. 6^n-1 b. 3^n-1 c. 6^n-3^n d. none of these

A family has two children. What is the probability that both the children are boys given that at least one of them is a boy ?

Assume that the birth of a boy or girl to a couple to be equally likely, mutually exclusive, exhaustive and independent of the other children in the family. For a couple having 6 children, the probability that their "three oldest are boys" is (a) (20)/(64) (b) (1)/(64) (c) (8)/(64) (d) none of these

One mapping is selected at random from all mappings of the set S={1,2,3,.... n} into itself. If the probability that the mapping is one-one is 3/32, then the value of n is 2 b. 3 c. 4 d. none of these