5 students stand in a row. Two particular students, Minho and Jisoo, must stand next to each other. How many arrangements are possible?
Answer and explanation
Correct answer: D. 48
- Step 1: Treat the pair as one block: there are 4 units to arrange in 4! = 24 ways. Step 2. Within the block, the two can swap: 2 ways. Step 3. Total = 24 x 2 = 48. Answer: 48. Why not the others: 120: That ignores the condition. 24: That treats the pair as one unit but forgets they can swap places. 12: That treats the two as fixed in one position.
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