Correct option: (B) 6/49
Explanation:
The total number of ways in which papers of 4 students can be checked by 7 teachers is 74. The number of ways of choosing 2 teachers out of 7 is 7C2. The number of ways in which they can check four papers is 24 , but this includes two ways in which all the papers will be checked by a single teacher. Therefore, the number of ways in which four papers can be checked by exactly 2 teachers is 24 – 2 = 14.
Therefore, the number of favourable ways is (7C2) (14) = (21) (14).
Thus, the required probability
