You have two jugs. One holds exactly 3 gallons and the other 5 gallons of water. You have unlimited supply of water. How do you fill 4 gallons of water into the five-gallon jug?

Riddle Answer# Riddles

## 3 Switches and 3 Bulbs

You are standing in a hallway next to 3 light switches that have been switched off. There is another room down the hallway with 3 light bulbs – all are incandescent light bulbs and each light bulb is operated by one of the switches in the hallway. The door to the room is closed and you cannot see the light bulbs from the hallway. How would you figure out which switch operates which light bulb, if you can enter the room with the light bulbs only once?

Riddle Answer## Frog in 30 Meter Well

A frog is at the bottom of a 30 meter well. Each day he summons enough energy for one 3 meter leap up the well.

Exhausted, he then hangs there for the rest of the day. At night, while he is asleep, he slips 2 meters backwards.

How many days does it take him to escape from the well?

Riddle Answer## Past the Bridge Guard

A guard is stationed at the entrance of a bridge. He is tasked to shoot anyone who tries to cross to the other side of the bridge, and to turn away anyone who comes in from the opposite side of the bridge. You are on his side of the bridge and want to escape to the other side.

Because the bridge is old and rickety, anyone who tries to cross it does so at a constant speed, and it always takes exactly 10 minutes to cross.

The guard comes out of his post every 6 minutes and looks down the bridge for any people trying to leave, and at all other times he sits in his post and snoozes. You know you can sneak past him when he’s sleeping, but the problem is that you won’t be able to make it all the way to the other side of the bridge before he sees you (since he comes out every 6 minutes, but it takes 10 minutes to cross).

One day a brilliant idea comes to you, and soon you’ve successfully crossed to the other side of the bridge without being shot. How did you do it?

Riddle Answer## The Lucas Ship Problem

“Every day at noon,” Lucas said, “a ship leaves Le Havre for New York and another ship leaves New York for Le Havre. The trip lasts 7 days and 7 nights. How many New York-Le Havre ships will the ship leaving Le Havre today meet during its journey to New York?

Riddle Answer