Dean was out with his car in search of a petrol pump. He saw a pump on the corner of a highway. There was a big board inviting customers: “Come one, come all, special scheme for a tank full of petrol.”
So Dean drove in and asked the attendant about the scheme and was directed to the manager. The manager said: “See mate, it is like this. You get your tank filled up full and bring the slip to me here in this cabin. I will guess one number between One and seven in my mind. All you have to do is to guess the correct number that is in my mind and if it matches, you go in the back cabin over there and you get free love.”
Dean got excited, ran back to his car, got his tank full and returned back to the manager with his slip. "All right” the manager said “I have decided a number between one and seven in my mind, make your guess.”
Dean said: “Seven.”
The manager said: “Oh sir, you were so close. The number was six. Dean was disappointed but not dejected. He gave another shot after a few days with the same result: “My god, your guess was close enough but not right. I am sorry sir, but no free love for you.”
Next day, Dean narrated the story to his friend, Martin over a drink and said: “Marty, the manager is a cheat. If he guessed seven and I say seven, what stops him from saying it was six? He can change the number in his mind anytime he wants to. It’s a scam, I tell you, that's what it is.”
Martin: “Hey wait Dean, that manager is no cheat and there is no scam, I assure you.’
Dean: “How can you be so sure?”
Martin: “My wife went there twice last week and won both times.”