When a mechanic wants to empty the gasoline tank of a car he fills a plastic tube with gasolime and dips one end of the tube into the tank He puts the other end into an empty container which is placed?

It'll have to be at a lower level than the car's gas tank, although, in reality, he would have to remove the fuel tank, disconnect the neck (as modern cars come with an anti-siphon neck), and either place the fuel tank at a higher point than the receptacle, or else use a vacuum pump (with diesel fuel, it's fine to use an electric one, and that's what we do at my shop.. gasoline is much more volatile, though).