If the papers of 4 students can be checked by any one of the 7 teachers, then the probability that all the 4 papers are checked by exactly 2 teachers is `2//7` b. `12//49` c. `32//343` d. none of these

If the papers of 4 students can be checked by any one of the 7 teachers, then the probability that all the 4 papers are checked by exactly 2 teachers is a. 2//7 b. 12//49 c. 32//343 d. none of these

If the papers of 4 students randomly distributed for checking among 7 teacher, then the probability that all the 4 papers are checked by exactly 2 teachers is n/m where n, m are natural number and HCF(n,m)=1 . Then number of positive divisiors of (n+m) is

Four persons are selected at random out of 3 men, 2 women and 4 children. The probability that there are exactly 2 children in the selection is a. 11/21 b. 9/21 c. 10/21 d. none of these

The probability that a leap year will have 53 Fridays or 3 Saturday is a. 2/7 b. 3/7 c. 4/7 d. 1/7

A box contains 24 identical balls of which 12 are white and 12 are black. The balls are drawn at random from the box one at a time with replacement. The probability that a white ball is drawn for the 4th time on the 7th draw is 5//64 b. 27//32 c. 5//32 d. 1//2

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

A bag contains 20 coins. If the probability that the bag contains exactly 4 biased coin is 3/4 and that of exactly 5 biased coin is 2/3, then the probability that all the biased coin are sorted out from bag is exactly 10 draws is 5/(10)(^(16)C_6)/(^(20)C_9)+1/(11)(^(15)C_5)/(^(20)C_9) b. 2/(33)[(^(16)C_6+5^(15)C_5)/(^(20)C_9)] c. 5/(33)(^(16)C_7)/(^(20)C_9)+1/(11)(^(15)C_6)/(^(20)C_9) d. none of these

A fair die is tossed eight times. The probability that a third six is observed in eight throw is (\ ^7C_(10)xx5^7)/(6^7) b. (\ ^7C_2xx5^2)/(6^8) c. (\ ^7C_2xx5^5)/(6^6) d. none of these

The area of a triangle with vertices at (-4,-1), (1,2) and (4,-3) is a. 17 b. 16 c. 15 d. none of these

Five different games are to be distributed among 4 children randomly. The probability that each child get at least one game is a. 1//4 b. 15//64 c. 5//9 d. 7//12