Question : 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
Answer : option
Solution :
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
with
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