After driving for about six hours, a trucker decides to pull over and sleep for a little while. As soon as he falls asleep, he is awoken by some knocks on the door of the cab. "Can you tell me the time, please?" asks a jogger. "Yeah, it's 4:30," answers the trucker. He falls asleep again, but he is awoken again by another jogger who wants to know the time. "It's 4:40!" yells the trucker. Deciding to really try to sleep a little, he writes on a piece of paper: 'I don't know the time.' He sticks the paper to his windshield. But he is awoken again -- "It's 5:25," says another jogger.
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