Since you didn't list choices, I can only give you some guidance on the problem.
A kilometer is the length of 1000 meters. And a meter is about as tall as a normal desk height. So a kilometer is a relatively long distance compared to a desk.
It is also about half the length of a mile, or about 2 times around a normal athletic track.
Look for items that are long distance like that.
Answer:
A straight angle is an angle of 180 degrees, so it looks like follows
Add up the 84 and 42 to get 126, then divide by 6 to get the number of tables which is 21. And the number of seats is 126 because you would need a seat for every person. Hope this helps.
The answer to your question is (1,9) :)