Logic Riddles

 

Question: A knight comes to a castle where his love is trapped. The castle is surrounded by a square moat that is 10 feet wide (it forms a square around the castle). The knight is able to fashion two 9 foot long planks to cross the moat.

How can he do this?


Question: Ants on a stick may only move left or right. If they bump into each other they bounce off of each other and immediately move in the opposite direction maintaining speed the entire time. The only time they change speed is when they fall off of the edge of the stick.

If 25 ants are randomly put on a 1 meter long stick moving 1 meter per second, what is the longest amount of time it could take for them to all fall off?

Question: You have a bag with 'N' strings in it. You randomly grab two ends and tie them together until there are no more loose ends.

In the end, what is the expected number of loops (strings tied to their own end)?

Ski Trip (medium)

Question: Mary and jack are newly weds and want to go on a ski trip... So jack starts planning. He books a flight for them to Colorado. When they get there Mary gets pushed off the cliff. There is a guy in Hawaii named Sam and he was reading the paper. He right away said the husband did it. How does he know? HINTS: they have never met in person, jack did not tell Sam, he was not guessing, and it did not say it in the news paper.

Passwords (medium)

Question: A man works at a high security facility. He goes to work in the morning on his computer. He types in his password, but it is incorrect. He remembers that the password changes every month, so he calls his boss. The man says, “Boss, the old password is out of date.” The boss replies, “Yes, the new password is different. But if you listen closely, you will figure it out. It has the same amount of letters, but no spaces.” The man thanks the boss and types the password in immediately. What was the new password and the old password?