In many ways can Ann, Bea, Cam, Don, Ella, and Fay be seated if Ann and Bea cannot be seated next to each other?
a) 240
b) 360
c) 480
d) 600
e) 720
a) 240
b) 360
c) 480
d) 600
e) 720
Bonjour Paris,Carloblacksun wrote:In many ways can Ann, Bea, Cam, Don, Ella, and Fay be seated if Ann and Bea cannot be seated next to each other?
a) 240
b) 360
c) 480
d) 600
e) 720
What you want to do is:
1) Find the possible seatings - without any restriction
A B C D E F = 6!
2) Have A & B sit next to each other and GLUE them together so they act like a Siamese twin
AB C D E F = 5!
and remember they can also switch places - :!:
BA C D E F = 5 !
3) Not If you subtract what you have just found from the all possible ways:
6! - 2 x 5 ! = 5! ( 6 - 2 ) = 120 x 4 = 480
