A class consists of 80 students, 25 of them are girls and 55 are boys. If 10 of them are rich and the remaining are poor and also 20 of them are intelligent, then the probability of selecting an intelligent rich girls is a.`5//128` b. `25//128` c. `5//512` d. none of these

Two players toss 4 coins each. The probability that they both obtain the same number of heads is a. 5//256 b. 1//16 c. 35//128 d. none of these

A cricket club has 15 members, of them of whom only 5 can bowl. If the names of 15 members are put into a box and 11 are drawn at random, then the probability of getting an eleven containing at least 3 bowlers is 7//13 b. 6//13 c. 11//158 d. 12//13

Five different marbles are placed in 5 different boxes randomly. Then the probability that exactly two boxes remain empty is (each box can hold any number of marbles) 2//5 b. 12//25 c. 3//5 d. none of these

A dice is thrown six times, it being known that each time a different digit is shown. The probability that a sum of 12 will be obtained in the first three throws is 5//24 b. 25//216 c. 3//20 d. 1//12

Five horses are in a race. Mr. A selects two of the horses at random and bets on them. The probability that Mr. A selected the winning horse is (A) 3/5 (B) 1/5 (C) 2/5 (D) 4/5

Kanchan has 10 friends among whom two are married to each other. She wishes to invite five of them for a party. If the married couples refuse to attend separately, then the number of different ways in she can invite five friends is a. ""^8C_5 b. 2xx ""^8C_3 c. ""^10 C_5-2xx ""^8C_4 d. none of these

In a class, 5% of the boys and 10% of the girls have an IQ more than 150. In the class 60% of the students are boys and rest girls. If a student is selected at random and found to have an IQ of more than 150, find the probability that the student is a boy.

In a class, 5% of the boys and 10% of the girls have an IQ more than 150. In the class 60% of the students are boys and rest girls. If a student is selected at random and found to have an IQ of more that 150, find the probability that the student is a boy.

From a class of 25 students, 10 are to be chosen for an excursion party. There are 3 students who decide that either all of them will join or none of them will join. In how many ways can the excursion party be chosen ?

A fair die is thrown 20 times. The probability that on the 10th throw, the fourth six appears is a. (.^20 C_(10)xx5^6)/6^(20) b. (120xx5^7)/6^(10) c. (84xx5^6)/6^(10) d. none of these