Four golfers are named Mr. Blue, Mr. Black, Mr. Brown, and Mr. White. They were contending in a golf tournament. The caddy was unaware about their identities, so he asked them their names.
- The 1st golfer responded, "The 2nd golfer is Mr. Black."
- The 2nd golfer replied, "I am not Mr. Blue."
- The 3rd golfer said, "Mr. White? That's the 4th golfer."
- The 4th golfer remained silent.
It is known that Mr. Brown is a liar, who always lies. Each of the other three golfers is a knight, who always speaks truthfully.
Which one of the golfers is Mr. Blue?
If golfer 1 were the liar (Brown), the 2nd would be neither Black nor Blue nor Brown, making him Mr. White. But no. 3, being another truth teller, would be stating a falsehood, a contradiction, so 1 is not Mr. Brown.
No. 2 can't be Mr. Brown, as then he'd be telling the truth, a contradiction. So no. 2 can't be either Mr. Brown or Mr. Blue. In fact, he's Mr. Black, as golfer 1 was telling the truth.
Now we know golfer 1 is either Mr. White or Mr. Blue.
The 3rd golfer, if telling the truth, is also either Mr. White (a contradiction of his statement) or Mr. Blue. But if he's Mr. Blue then 1 is Mr. White, contradicting 3's statement.
So the 3rd golfer is Mr. Brown, the liar. The 2nd golfer is Mr. Black. The 4th golfer is known from 3's lie not to be Mr. White, who is thus the 1st golfer. That makes the 4th golfer Mr. Blue.
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Posted by Charlie
on 2023-02-13 08:38:01 |
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