[JEE Advanced 1991] $18$ guests sit $9$ on each side of a long table. Four particular guests want one side, three others the opposite side. Find the number of seating arrangements.
$18$ guests sit $9$ on each side of a long table. Four particular guests want one side, three others the opposite side. Find the number of seating arrangements.
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· 1mo ago
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Answer: $\binom{11}5\cdot9!\cdot9!$.
Of the remaining $11$ guests, choose $5$ for the first side (it needs $9-4=5$ more): $\binom{11}5$; then arrange each side: $9!\cdot9!$.
JEE Advanced 1991 · Permutations and Combinations — verified solution by the Vidaara Team.
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