Question

In how many ways can 7 people be seated at a roundtable if 2 particular people must notsit next to each other?

• A. 5040
• B. 240
• C. 480
• D. 720

Answer 1

Answer: (C)

480

Answer 2

For circular arrangement of $n$ people the formula = $(n - 1)!$

Given that 7 people in the question so it will be $6!$ = 720 (without any restrictions)

In question it is given that 2 particular people must not sit next to each other

making it $5!$ for two people it will be $5! \times 2 =240$

In restricted cases from the total arrangements = 720 - 240 = 480

The correct option is (C): 480