Question

in how many ways can 7 persons be seated around two circular tables when 4 persons canston the first table and 3 cansiton the other?

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Answer 1

Answer:

Two round tables: one to seat 4 out of 7 and the other to seat remaining 3

No. of different selections for seating 4 out of 7 on 1st table of is 7C4 and number of permutations for each such selection is (4-1)! or 3! (Note round Table)

So different ways of seating on 1st table = 7C4x3!

For each of the above ways of seating on 1st table, different ways of seating on 2nd table is 3C3x2!

So different ways of seating on the 1st and 2nd table taken together is (7C4x3!)x(3C3x2!) = (35x6)x(3x2) = 1260