CA Foundation · Quantitative Aptitude · Seating Arrangements
In how many ways can 7 persons be seated around a circular table so that two particular persons, Arjun and Balan, do NOT sit next to each other?
The answer is 480. Total circular arrangements are 6! = 720. Arrangements with the two together are 5! × 2 = 240. Subtracting the together cases from the total gives 480 arrangements where they are not adjacent.
- A240
- B480Correct
- C600
- D720
Explanation
Total circular arrangements of 7 persons = (7-1)! = 720. If Arjun and Balan are together, treat them as one unit: 5! = 120 arrangements, times 2 internal orders = 240. Not together = 720 - 240 = 480. The value 600 results from forgetting to multiply by 2.
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