Imagine: if you add one person, the tables for 3, 5, 7 and 9 people are just right.

Because the least common multiple of 3,5,7,9 =3 15.

So the total number of people should be 3 15m- 1.

And 1 1 is divisible by 3 15m- 1.

3 15*8- 1=25 19

∫ 1 1 is divisible by 25 19.

So there are at least 25 19 people.

2519/11= 229 (Zhang)

So there are 229 tables in the room.

A: This room has 25 19 people and 229 tables.