Question
In how many ways can 5 persons be seated around a round table so that two of them must always be together?
Solution
Tie the two
Number of arrangements = 
Mix with remaining
Now, we have 3 + 1 = 4 persons to sit around a round table.
The number of permutations = (4 - 1)! = 3! = 6
Hence, the total number of arrangments when the two persons sit together
= 2 x 6 = 12
