Yes.
It depends on the dimensions of the room. As an extreme example, if the room is 1 ft * 1500 ft , not a single table will fit.
More than 60 inches square!
For banquets, a 6 ft (72inch) round table is typically used to seat 10 people comfortably
16. I assume each table is 5 feet wide. 400 sq ft means the room could be 20 X 20. That would mean 4 rows of 4 tables.
10 people comfortably, but you can fit up to 12 people if needed. Any less than 9 people at a 72" table is too much room.
Assuming you are talking about a 60" diameter table and a regular octagon (regular being of equal sides) you would need a room that is 60" across. If you wanted chairs, add 30".
400
16 x 16 = 256
35
The fact that the tables are round is a distraction as (since most rooms are rectangular) each table would have to fit in a square 48 inches by 48 inches (or 4 foot by 4 foot). This means that each table will take up 4*4 = 16 square feet. If you divide 16 into 600 you come up with 37.5 tables so in theory you could fit 37 tables into it. However, if the room was 1 foot wide and 600 feet long you would not be able to fit any tables into it. Only if the room was irregularly shaped could you fit the maximum number of 4 ft round tables, each of which has the area (pi)(22) or about 12.57 square feet. A total area of 600 square feet would fit the "area" of 47.75 of the tables. By arranging the tables in staggered rows, a rectangular room could fit between 37 and 42 tables, depending on the room width.
144 assuming no waste.
A round table takes up more room because there is more area to the table, where as a square table can be pushed into a corner or left in the middle of the room and the edges distract from the remaining surroundings and it's easier to get around.