In how many ways can we seat 7 people in a round table with a certain 3 people not in consecutive order?
Let's call the seats A,B,C,D,E,F,G
Then, the possibilities for the chair positions for the three people are :
A C E B D F C E G
A C F B D G
A D F B E G
And each of the three people can be assigned to these seats in 3! ways = 6 ways
And the other 4 people can be arranged in 4! ways = 24 ways for each arrangement above
So we have
7 position possibilities * 6 arrrangements of the three people for each position possibility* 24 arrangements of the other 4 people = 1008 ways
As Melody often says....."That's what I think"
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In how many ways can we seat 7 people in a round table with a certain 3 people not in consecutive order?
I do not understand the question ://
What does it mean that the 3 people are not in consecutive order?
I will take it to mean that all 3 of these people cannot sit together. I think CPhill has interpreted it the same way.
2 CAN sit together but not all 3
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ok, as CPhill said there are 3!=6 different ways these three can sit together - that is ignoring everyone else.
Mmm Altogether there are 6! = 720 ways to sit 7 people at a table (rotations are counted as the same)
So CPhill's answer can't be right. Sorry Chris. ![]()
My nexty task is to try and work out how many ways the group can be seated with the 3 siting next to each other.
Now if I tie the tree together and treat them like one person then there are 4 real people plus the triplet and these can be seated in 4! ways = 24 ways.
But there are 6 ways the triplets can be tired so that is 24*6=144 ways the three can be together
so
The number of ways that they can be seated if those three are not all together must be 720-144 = 576 ways
That is what I think anyway LOL
Yeah, Melody....I see that I'm probably wrong.....I'm just trying to figure out my mistake....do you see it??? ....did I "double-count" somehow???
[ My answer seems "logical"......LOL!!!! ]
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Chris, haven't you tried to put the three people together rather than NOT together ?
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"7 position possibilities * 6 arrrangements of the three people for each position possibility* 24 arrangements of the other 4 people = 1008 ways"
I am going to assume that is what you have tried to find. And I will look at your logic.
Yes there are 6 ways to seat the 3 that will remain together - in relation to each other.
So we will take one of these arrangements and seat these three people.
Noy you are right i believe, there are 4! = 24 arangements for the other 4
6*24=144 Yes so far I agree.
The you multiply this andwer by 7..... Why did you do that ?