
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.



The bank robber was wearing a blue hat. Say Jake
is the liar and Joe is the truthteller. 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 truthteller. 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

