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Colorful Crime
 
Q Read this story. Then figure out what color hat the bank robber was wearing. But remember one thing: one of the brothers always tells the truth, and the other always lies ? and we don't know which is which.

After a bank robbery, two guys ran out of the bank. One was wearing a red baseball cap. The other was wearing a blue baseball cap. The police didn't know which one was the criminal. Luckily, Jake saw the robbery and could tell the police what color hat the robber was wearing. Jake's brother Joe later told their sister, Jenny, what happened. "Jake said the robber was wearing a red hat," he said.


 
A The bank robber was wearing a blue hat. Say Jake is the liar and Joe is the truth-teller. That means Jake actually did say that the robber was wearing a red hat. But whatever Jake says is false, so the robber's hat was blue.

Now let's say that Joe is the liar and Jake is the truth-teller. That means that Jake really told his friends that the robber was wearing a blue hat. And since Jake always tells the truth, the robber's hat was, indeed blue. The answer is blue ? either way.

Source:Usborne Brain Puzzles,p.20