Permutations And Combinations Question 45

Question: 12 persons are to be arranged to a round table. If two particular persons among them are not to be side by side, the total number of arrangements is [EAMCET 1994]

Options:

A) $ 9(10\ !) $

B) $ 2(10\ !) $

C) $ 45(8\ !) $

D) $ 10\ ! $

Show Answer

Answer:

Correct Answer: A

Solution:

  • 12 persons can be seated around a round table in $ 11\ ! $ ways. The total number of ways in which 2 particular persons sit side by side is $ 10\ !\ \times \ 2\ ! $ . Hence the required number of arrangements $ =11\ !\ -10\ !\ \times 2\ !\ =9\times 10\ ! $ .



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