Fill the Jug | Puzzles for Interview - Interview Preparation PDF Download

Introduction

If you have two jugs, one 4 liters and the other 3 liters, and you want to get 2 liters of water in the 4 liter jug, then this article will guide you through the steps. The jugs don't have any measuring marks, and they can be filled or emptied any number of times.

Solution

Thinking Recursively:

To get 2 liters of water in the 4 liter jug, we need to have either 1 liter of water in the 3 liter jug and 1 liter of water in the 4 liter jug, or 2 liters of water in the 4 liter jug. We can achieve this by following these steps:

First Approach:

1. Fill the 4 liter jug with water completely.
2. Pour the water from the 4 liter jug into the 3 liter jug, leaving 1 liter of water in the 4 liter jug and 3 liters of water in the 3 liter jug.
3. Empty the 3 liter jug.
4. Pour the 1 liter of water from the 4 liter jug into the empty 3 liter jug, leaving 0 liters of water in the 4 liter jug and 1 liter of water in the 3 liter jug.
5. Fill the 4 liter jug with water completely again.
6. Pour the water from the 4 liter jug into the 3 liter jug, which already has 1 liter of water, until the 3 liter jug is full, leaving 2 liters of water in the 4 liter jug.

Second Approach:

1. Fill the 3 liter jug with water completely.
2. Pour the water from the 3 liter jug into the 4 liter jug.
3. Fill the 3 liter jug with water again.
4. Pour the water from the 3 liter jug into the 4 liter jug until the 4 liter jug is full, leaving 2 liters of water in the 3 liter jug.
5. Empty the 4 liter jug.
6. Pour the 2 liters of water from the 3 liter jug into the empty 4 liter jug, resulting in 2 liters of water in the 4 liter jug.

Conclusion

In either approach, we need to follow 6 steps to get 2 liters of water in the 4 liter jug. It's important to note that we can use these jugs in different ways to get various amounts of water.