An Engineer was unemployed for long time. He could not find a job so he opened a medical clinic and puts a sign up outside: "Get your treatment for $50, if not treated get back $100." One Doctor thinks this is a good opportunity to earn $100 and goes to his clinic. Doctor: "I have lost taste in my mouth." Engineer: "Nurse, please bring medicine from box 22 and put 3 drops in the patient's mouth." Doctor: "This is Petrol!" Engineer: "Congratulations! You've got your taste back. That will be $50." The Doctor gets annoyed and goes back after a couple of days later to recover his money. Doctor: "I have lost my memory, I cannot remember anything." Engineer: "Nurse, please bring medicine from box 22 and put 3 drops in the patient's mouth." Doctor: "But that is Petrol!" Engineer: "Congratulations! You...