Richard is a strange liar. He lies on six days of the week, but on the seventh day he always tells the truth. He made the following statements on three successive days:
Day 1: "I lie on Monday and Tuesday."
Day 2: "Today, it's Thursday, Saturday, or Sunday."
Day 3: "I lie on Wednesday and Friday."
The Question: On which day does Richard tell the truth?
I'm posting one puzzle, riddle, math, or statistical problem a day. Try to answer each one and post your answers in the comments section. I'll post the answer the next day. Even if you have the same answer as someone else, feel free to put up your answer, too!
Tuesday, July 17, 2007
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Well, we know that the truth day cannot be Thursday, Saturday, or Sunday, because then all other days (including all days mentioned on day 1 and day 3) would be lying days, making his first and third statements true, but we know two out of three have to be lies.
ReplyDeleteSo the truth day has to be Monday, Tuesday, Wednesday, or Friday. Tuesday is the only one that works. Day 1 is Sunday.
Very well stated, Abe.
ReplyDeleteExcellent analysis, Professor Don
ReplyDeleteSplendid comment, Andy.
ReplyDelete