Eighteen guests have to be seated, half on each side of a long table. Four particular guests desire to sit on one particular side and three others on the other side. Determine the number of ways in which the sitting arrangements can be made.

Out of guests half i.e. to be seated on side A and rest 9 on side B. Now out of 18 guests, 4 particular guests desire to sit – on one particular side say side A and other 3 on other side B. Out of rest 18 – 4 – 3 = 11 guests we can select 5 more for side A and rest 6 can be seated on side B. Selection of 5 out of 11 can be done in ¹¹ C₅ ways and 9 guests on each sides of table can be seated in 9! x 9! Ways. Thus there are total ¹¹ C₅ x 9! x 9! Arrangements.