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In how many ways can they be seated around a circular table such that the men and women occupy the alternate position?

(a) 288
(b) 144
(c) 72
(d) 720

1 Answer

6 votes

To find out the number of ways to seat an equal number of men and women alternately at a circular table, calculate (n-1)! arrangements for the men and n! for the women. Since circular arrangements are invariant under rotation, divide by n, resulting in a total of (n-1)! x n!. For 4 men and 4 women, this results in 144 arrangements. The correct answer is option b.

The question concerns the number of ways people can be seated around a circular table such that men and women occupy alternate positions. This is a combinatorial problem often solved using permutations and combinations. Assuming equal numbers of men and women, there are n! ways to arrange n men and (n-1)! ways to arrange n women around a circular table in alternate positions. However, because a circular arrangement is considered the same when rotated, we divide the result by n to correct for overcounting. Assuming n is the common number of men and women:

  1. Arrange the men in (n-1)! ways (since rotating the circle does not create a new arrangement).
  2. For each arrangement of men, there are n! ways to insert women into alternate positions.
  3. Multiply the arrangements of men and women to find the total, which is (n-1)! x n!.

If there are 4 men and 4 women, the calculation would yield 3! (men) x 4! (women) = 6 x 24 = 144 possible arrangements.

Therefore, the correct answer is (b) 144.

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