Skip to content

CA Foundation · Quantitative Aptitude · Permutations and Combinations

Eight members of a family in Lucknow sit around a circular table. Two particular members, Mohan and Sita, must always sit next to each other. In how many ways can the seating be arranged?

The answer is 1440. Treating the two members as a single block gives 7 units in a circle, arranged in 6! = 720 ways. The block's two members can be ordered in 2 ways, so 720 × 2 = 1440. Forgetting the internal swap gives only 720.

  1. A720
  2. B5040
  3. C1440Correct
  4. D10080

Explanation

Treat Mohan and Sita as one unit, so there are 7 units around the table: (7-1)! = 720 ways. The pair can swap places internally in 2! = 2 ways. Total = 720 × 2 = 1440. Option 720 omits the internal arrangement of the pair.

Did you get it right without looking?

One question tells you little. A timed set on Permutations and Combinations shows your real accuracy, how long you take and where you lose marks.

Practise Permutations and CombinationsFree diagnostic mock

More Permutations and Combinations questions