Seven people including Bush and Putin are to be seated at a round table. In how many ways can the seating plan be arranged such that there is exactly one person who sits between Bush and Putin?
Seven people including Bush and Putin are to be seated at a round table. In how many ways can the seating plan be arranged such that there is exactly one person who sits between Bush and Putin?
Seat bush and Putin first.
These problems always have the table floaing in space so any one chair is equaivalent to any other.
so
there are 2 ways that Bush and Putin can be seated.
Now there is a choice of 5 people that can be seated between them.
so that is 2*5 ways so far.
Now there are 4 more people to sit that is 4! ways
so altogether there is 2*5*4! = 10*24 = 240 ways
Seven people including Bush and Putin are to be seated at a round table. In how many ways can the seating plan be arranged such that there is exactly one person who sits between Bush and Putin?
Seat bush and Putin first.
These problems always have the table floaing in space so any one chair is equaivalent to any other.
so
there are 2 ways that Bush and Putin can be seated.
Now there is a choice of 5 people that can be seated between them.
so that is 2*5 ways so far.
Now there are 4 more people to sit that is 4! ways
so altogether there is 2*5*4! = 10*24 = 240 ways