In the dead of night, four people need to cross a rickety bridge. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge: Person A…
A king had received a gift of 100 bottles of wine but suspected one had been poisoned. The king placed 100 wine bottles on the table, 99 of which contained normal wine and one which contained poison. Even a sip of the poisoned wine was enough to kill. The poison was indetectable, meaning it wouldn’t…
Imagine a round manhole (a circular hole cover) and a square manhole. Both of them have the same area, and both of them are designed such that the cover should not fall into the hole regardless of how you orient it. Now, the round manhole cover won’t fall into the round hole because the diameter…
Three people check into a hotel room. The receptionist says the bill is £30, so each guest pays £10. Later the receptionist realizes the bill should have only been £25. To correct this, he gives the porter £5 to return to the guests. On the way to the room, the porter realizes he cannot divide…
Welcome to “Cow or Car”! You’re a part of a game show with three doors. Behind one door is a brand-new car, and the other two doors reveal a cow. The game show host, who knows what’s behind each door, asks you to pick one door. After you pick a door (say Door #1), the…
Here’s a slight variation on a classic brainteaser, albeit it’s still a tough one! Three extremely skilled logicians, A, B, and C, are seated around a table. A knows his own IQ is 120, B knows hers is 130, and C knows his is 140. What they don’t know is each other’s IQ. However, they…