Longer-wider problem to solve

I took another problem from the same collection as before, this time for 6th grade. It reads:

A rectangular kitchen table is three times as long as it is wide.
If it were 3 m shorter and 3 m wider it would be a square.
What are the dimensions of the rectangular table?

I'll let you try it first, but don't post the solution as a comment into this post. Let others try solve it too.

(You can get an extra point for answering this: Is this a realistic kitchen table?)