SOLUTION: in how many ways can 8 people be seated in a row such that two brothers must not sit next to each other?

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Question 883337: in how many ways can 8 people be seated in a row such that two brothers must not sit next to each other?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
If you disregard the problem of the
brothers not sitting together, there are
+8%2A7%2A6%2A5%2A4%2A3%2A2%2A1+=+8%21+ ways
From this you can subtract all the ways
the brothers can be seated together
------------------------------------
B B * * * * * *
* B B * * * * *
* * B B * * * *
* * * B B * * *
* * * * B B * *
* * * * * B B *
* * * * * * B B
There are +7+ ways they can sit together
so, the answer is +8%21+-+7+
You might get a 2nd opinion, but
that's my guess