Brainteasers

February 20, 2018 Brainteaser

The Lion And The Unicorn

The lion and unicorn live in the same forest. The lion lies every Monday, Tuesday and Wednesday, and on the other days of the week, he speaks the truth. The unicorn lies on Thursdays, Fridays and Saturdays, and on the other days of the week, he speaks the truth.

One day, the lion said, “Yesterday, I was lying.”

The unicorn said, “So was I.”

On which day did this conversation take place?

 

Answer: There is no day of the week on which both animals lie. Therefore, one of them had to be speaking the truth. They both speak the truth on Sunday, but if the lion had made this statement, he would be lying, because he speaks the truth on Saturday, too. This means one of the animals was lying.

 

The only day on which this statement makes sense is Thursday, with both animals referring to Wednesday. The lion’s statement is true, and he lied yesterday. The unicorn is lying now, and he spoke the truth yesterday.