## Favorite (no-tricks all logic) puzzles

None of these are puzzles I made up, these are puzzles that are relatively well known and easily found on the Internet. I don't like puzzles with gotcha tricks-- such as har har I gotcha, you read the question too fast. These are some solid logic puzzles.

1. Water bucket 3L, 5L
You have a 3 and a 5 litre water container, each container has no markings except for that which gives you it's total volume. You also have a running tap. You must use the containers and the tap in such away as to exactly measure out 4 litres of water. How is this done? Can you generalise the form of your answer?

2. Chicken fox corn
A man has to get a fox, a chicken, and a sack of corn across a river. He has a rowboat, and it can only carry him and one other thing. If the fox and the chicken are left together, the fox will eat the chicken. If the chicken and the corn are left together, the chicken will eat the corn. How does the man do it?

3. Light bulb puzzle
Suppose that you are standing in a hallway next to 3 light switches, which are all off. There is another room down the hallway, where there are 3 incandescent light bulbs – each light bulb is operated by one of the switches in the hallway. Because the light bulbs are in another room, you can not see them since you are standing in the hallway. How would you figure out which switch operates which light bulb, if you can only go the room with the light bulbs one time, and only one time?

4. Light bulb puzzle
You have two ropes and a lighter. Each rope has the following property: If you light one end of the rope, it will take one hour to burn to the other end. They don't necessarily burn at a uniform rate. How can you measure a period of 45 minutes?

5. Light bulb puzzle
You have two ropes and a lighter. Each rope has the following property: If you light one end of the rope, it will take one hour to burn to the other end. They don't necessarily burn at a uniform rate. How can you measure a period of 45 minutes?

6. Counterfeit coin weighingThere are eight identical-looking coins; one of these coins is counterfeit and is known to be lighter than the genuine coins. What is the minimum number of weighings needed to identify the fake coin with a two-pan balance scale without weights?