In how many ways can 4 boys and 4 girls be seated in a circle such that no two boys sit next to each other?
Answer and explanation
Correct answer: D.
- Step 1: First seat the 4 girls in a circle: circular permutations of 4 people is ways.
- Step 2: The seated girls create 4 distinct gaps between them.
- Step 3: The 4 boys must be placed into these 4 distinct gaps: linear arrangement in 4 designated seats is ways.
- Step 4: Apply fundamental counting principle: ways.
Answer
144.
Why not the others: '' uses ; '' is ; '' multiplies by 2 unnecessarily.
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