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Four children and four adults are to be seated at a circular table.
In how many different ways can they be seated if all the children are next to each other,
and all the adults are next to each other? (Two seatings are considered the same
if one can be rotated to form the other.)
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Again, as in one of problems that I solved for you earlier today, we subdivide
the people in two separate groups. One group is of 4 children; the other group
is of 4 adults.
First, we consider all possible circular permutations of these two groups as
of two whole objects.
The number of all possible circular permutations of these two groups is
(2-1)! = 1! = 1.
Next, there are 4! = 24 permutations inside the group of 4 children and
another 4! = 24 permutations inside the group of 4 adults.
These permutations are independent and produce 24*24 = 576 permutations,
in total.
So, there are 576 circular permutations, in all. ANSWER
Solved.