Permutation and CombinationHard
Question
A train is going from London to Cambridge stops at 12 intermediate stations. 75 persons enter the train during the journey with 75 different tickets of the same class. Number of different sets of tickets they may be holding is:
Options
A.78C3
B.91C75
C.84C75
D.none
Solution
Total no. of different tickets is
12 + 11 + 10 + ......+ 1 = 78
Hence required no. = 78C75 = 78C3
12 + 11 + 10 + ......+ 1 = 78
Hence required no. = 78C75 = 78C3
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