Measure 4L using given 3 buckets | Puzzles for Interview - Interview Preparation PDF Download

Introduction

Suppose you have an 8L, 5L, and a 3L bucket, but they do not have any measurement lines on them. Your task is to measure exactly 4L of water using only these three buckets. The good news is that you have as much extra water as you need.

Solution

Method 1 - When You Can Throw Water Out of the Bucket

1.1 Using the 8L, 5L, and 3L buckets, follow these steps:

• Fill the 8L bucket full
• Pour the water from the 8L bucket to the 3L bucket. The water remaining in the 8L bucket is now 5L
• Empty the 3L bucket
• Pour the remaining water from the 8L bucket to the 3L bucket. The water remaining in the 8L bucket is now 2L
• Empty the 3L bucket
• Pour the remaining 2L water from the 8L bucket to the 5L bucket
• Repeat the above steps, and you will have 4L of water in the 5L bucket

1.2 Using the 8L, 5L, and 3L buckets, follow these steps:

• Fill the 5L bucket full
• Pour the water from the 5L bucket to the 3L bucket. The water remaining in the 5L bucket is now 2L
• Empty the 3L bucket
• Pour the remaining water from the 5L bucket to the 8L bucket. The water remaining in the 8L bucket is now 2L
• Repeat the above steps, and you will have 4L of water in the 8L bucket

Method 2 - When You Cannot Throw Water Out of the Bucket

2.1 Using the 8L, 5L, and 3L buckets, follow these steps:

• Fill the 8L bucket full
• Pour the water from the 8L bucket to the 5L bucket. The water remaining in the 8L bucket is now 3L
• Pour the water from the 5L bucket to the 3L bucket. The water remaining in the 5L bucket is now 2L
• Pour the water from the 3L bucket to the 8L bucket. The water in the 8L bucket is now 6L, and the 3L bucket is empty
• Pour the water from the 5L bucket to the 3L bucket. The water in the 3L bucket is now 2L, and the 5L bucket is empty
• Pour the water from the 8L bucket to the 5L bucket. The water remaining in the 8L bucket is now 1L, and the 5L bucket is full
• Pour the water from the 5L bucket to the 3L bucket. The water remaining in the 5L bucket is now 4L, as the 3L bucket already had 2L of water.
• You have now measured 4L of water in the 5L bucket

• Fill the 5L bucket full
• Pour the water from the 5L bucket to the 3L bucket. The water remaining in the 5L bucket is now 2L
• Pour the remaining water from the 5L bucket to the 8L bucket. The water remaining in the 8L bucket is now 2L
• Transfer the water from the 3L bucket to the 5L bucket. The 5L bucket is now full
• Repeat the above steps, and you will have 4L of water in the 8L bucket

Conclusion

Measuring 4L of water using 3 buckets without any measurement lines might seem difficult, but you can do it by following the steps mentioned above. The key is to pour the water from one bucket to another carefully and systematically.