CA Foundation · Quantitative Aptitude · Seating Arrangements
In how many ways can 5 persons be seated around a circular table so that two particular persons, Gita and Hari, do NOT sit next to each other?
The answer is 12. All 5 persons can be seated round a table in 4! = 24 ways. Those with Gita and Hari adjacent number 3! x 2 = 12. Subtracting the adjacent cases from the total leaves 12 arrangements.
- A6
- B12Correct
- C18
- D24
Explanation
Total circular arrangements of 5 persons = (5-1)! = 24. Arrangements with Gita and Hari together: treat them as one unit, giving 4 units in a circle, (4-1)! = 6, times 2 for their internal order = 12. Not together = 24 - 12 = 12. Choosing 18 comes from forgetting the internal order factor of 2.
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