CA Foundation · Quantitative Aptitude · Permutations and Combinations
In how many ways can 5 people, Aarav, Bhavna, Chirag, Divya and Esha, be seated in a row if Aarav and Bhavna must sit next to each other?
There are 48 seating arrangements. Treating Aarav and Bhavna as a single block leaves four units to arrange in 4! = 24 ways, and the two within the block can swap places in 2 ways, so 24×2 = 48. Forgetting the swap gives 24.
- A24
- B48Correct
- C120
- D72
Explanation
Treat Aarav and Bhavna as one block. The 4 units (block plus 3 others) can be arranged in 4! = 24 ways, and the pair can be ordered internally in 2! = 2 ways. Total = 48. Option 24 forgets the internal order.
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