Fundas of economics

Just coming back from an economics class. And damn it!! I haven't seen someone better than the professor at lullabies.
The only time that I woke up was to have some laughs over this:
"Once a physicist, a chemist and an economist were hungry and pondering over how to open a can of food.
The physicist tried first to open the can. He said he knew a technique to apply force which would crack open the can. He applied force to it and failed.
The Chemist tried next. He said he knew a chemical to melt the can open. He too failed.
Finally the economist smiled with confidence. He said lets assume that the can is open........."







Yes the joke is over!