Question:
In how many ways can 5 different books be arranged on a shelf if two particular books must be together?
In how many ways can 5 different books be arranged on a shelf if two particular books must be together?
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For arrangements with constraints, treat restricted items as a single unit and multiply by their internal arrangements.
Updated On: Jul 24, 2025
- 24
- 48
- 120
240
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The Correct Option is B
Solution and Explanation
Treat the two books as a single unit. Number of units = \( 4 \) (3 individual books + 1 pair).
Arrange 4 units: \( 4! = 24 \).
Arrange the two books within the pair: \( 2! = 2 \).
Total ways = \( 24 \times 2 = 48 \).
Thus, the answer is 48.
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