A giant ship's engine broke down and no one could repair it, so they took it to a Mechanical Engineer with over 40 years of experience.
He inspected the engine very carefully, from top to bottom. After seeing everything, the engineer unloaded the bag and pulled out a small hammer.
He knocked something gently. Soon, the engine came to life again. The engine has been fixed!
7 days later the engineer mentioned that the total cost of repairing the giant ship was $ 10,000 to the ship owner
"What ?!" said the owner.
"You did almost nothing. Give us a detailed bill."
The answer is simple:
Tap with a hammer: $ 2
Know where to knock & how much to knock: $ 9,998
