CA Foundation · Quantitative Aptitude · Seating Arrangements
Seven friends are to sit around a circular table. In how many ways can they be seated if two particular friends, Hari and Isha, must NOT sit next to each other?
The answer is 480. Seven people around a circle can be seated in 720 ways. Treating the two as one block gives 5! x 2 = 240 ways with them together. Subtracting these from the total leaves 480 ways in which they are apart.
- A240
- B480Correct
- C600
- D720
Explanation
Total circular arrangements of 7 persons = 6! = 720. Arrangements with Hari and Isha together = 5! x 2 = 240. Not together = 720 - 240 = 480. The option 240 is only the 'together' count, and 600 comes from wrongly subtracting just 5!.
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