Sales Trick

A petrol station owner in Dublin was trying to increase his sales, so he put up a sign that read, “Free Sex with Every Fill-Up.”
Paddy pulled in, filled his tank and asked for his free sex. The owner told him to pick a number from 1 to 10, and said that if he guessed correctly, he would get his free sex. Paddy guessed 8, and the proprietor said, “You were very close, the lucky number was 7. Sorry, no sex this time.”
A week later, Paddy, with his friend Mick, pulled in for another fill-up. Again Paddy asked for his free sex. The proprietor again gave him the same story, and asked him to guess the correct number. Paddy guessed 2. The proprietor said, “Sorry, it was 3, you were very close, but no free sex this time.”
As they were driving away, Mick said to Paddy, “I think that game is rigged and he doesn’t really give away free sex at all.”
Paddy replied, “No it’s genuine enough Mick. My wife won twice last week.”