-A GP has a leak in his basement. Although it's weekend, he calls the plumber and asks him to come immediately.

The plumber arrives and the doctor takes him to the basement, which is pretty flooded.

The plumber takes the case into consideration and asks: "Do you perhaps a paracetamol pill for me?"

The doctor is surprised, but go get the requested pill without asking further questions.

Back in the basement the plumber takes pill and throws it in the water.

"So," said the plumber, "I'm off again, but if it's not over on Monday you should call me."

Farmer calls a plumber, his water pump has stopped working.

Plumber arrives and has a good look at the pump then takes out a big hammer and hits the pump.

It starts working again.

He then presents the farmer with a bill for $50.

The farmer complains, $50 all you did was come here and hit the pump with a hammer it only took you a few seconds, I want an itemized account.

OK says the plumber and writes :

Traveling to and from the farm $10

Hitting the pump with a hammer $5

Knowing where to hit $35

Total $50

Mechanics know that to get things working you sometimes have to use a hammer.

Engineers know

1 what size hammer

2 where to hit

3 how hard

4 how many times

5 How to write the bill so lunch gets paid for.