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, 5 with no repetitions. The probability that the number is divisible by 5 is a. 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 a. 3//4 b. 1//2 c. 1//3 d. none of these

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

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 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 each born child is equally likely to be a boy or a girl. If a family has two childeren what is the conditional probability that both gives both are girls given that i. the youngest is a girl ii. Atleast one is a girl

Let A ,B ,C ,D be independent events such that P(A)=1//2,P(B)=1//3, P(C)=1//5, a n dP(D)=1//6. Then theprobability that none of A ,B ,C ,a n dD occurs a. 1//180 b. 1//45 c. 1//18 d. none of these

If the sum to infinity of the series 1+2r+3r^2+4r^3+ is 9/4, then value of r is 1//2 b. 1//3 c. 1//4 d. none of these

The probability that a student selected at random from a class will pass in Mathematics is 2/3 and the probability that he passes in Mathematics and English is 1/3 . What is the probability that he will pass in English if it is known that he has passed in Mathematics ?