Problem
COM-B1-M02-P020 Exactly One Person Between Two
#20
★★★☆☆ Level 3 of 5
In how many ways can \(5\) people sit at a round table if exactly one person must sit between Anton and Boris?
Fix Anton.
Fix Anton. Boris has \(2\) seats at distance two around the circle from Anton. Arrange the remaining \(3\) people in \(3!\) ways. Answer: \(2\cdot3!=12\).
Circular problem where a block is not the most convenient.