Just Part I. I had (8! x 3!)/10 ; and the answer says (7! x 3!).
Could someone explain to me which one is right and why please?
Thank You.
Let us consider an arrangement where the teenagers sit together.
The rest of the seven persons who are not teenagers can be arranged in 7! ways
The three teenagers can themselves sit in 3! ways.
therefore the total number of arrangements are
7!X3!