Measuring Water Without Extra Equipment: A Logical Solution Using Beakers

Imagine you are given a bottle of water and three beakers of varying sizes. One beaker holds 30 milliliters (ml), another 40 ml, and the largest holds 200 ml. Your challenge is to measure exactly 20 ml of water using these beakers without any additional tools. This article explores a logical solution to the problem in a step-by-step manner.

Step-by-Step Solution Using Beakers

Here's how you can measure exactly 20 ml of water using the beakers provided:

Fill the 30 ml beaker: Start by filling the 30 ml beaker from the bottle of water. Now, you have 30 ml in the 30 ml beaker. Pour into the 40 ml beaker: Carefully pour the water from the 30 ml beaker into the 40 ml beaker. Now, the 40 ml beaker has 30 ml, and the 30 ml beaker is empty. Rinse the 30 ml beaker: Fill the 30 ml beaker again from the bottle of water. Pour into the 40 ml beaker: Pour the water from the 30 ml beaker into the 40 ml beaker until it is full. Since the 40 ml beaker already has 30 ml, you can only add 10 ml more to it. This will leave you with exactly 20 ml in the 30 ml beaker.

By following these steps, you have successfully measured exactly 20 ml of water using the beakers provided, without any additional equipment.

Different Perspectives and Solutions

There are other proposed solutions for measuring exactly 20 ml of water:

Fill the 200 ml beaker: Another approach is to fill the 200 ml beaker with water, then use it to fill the 30 ml beaker six times, discarding the water from the 30 ml beaker each time. This will leave you with 20 ml of water in the 200 ml beaker. Logical Strategy: Using logical thinking, recognize that 40 ml - 30 ml 10 ml. Thus, you can accurately pour off 10 ml from the 30 ml beaker. Here’s how: Fill the 30 ml beaker and pour into the 40 ml beaker: Fill the 30 ml beaker, then pour it into the 40 ml beaker. Now, the 30 ml beaker is empty, and the 40 ml beaker has 30 ml. Top up the 40 ml beaker: Fill the 30 ml beaker again and use it to top up the 40 ml beaker. When the 40 ml beaker is full, the 30 ml beaker will have exactly 20 ml left.

Conclusion

While some solutions involve discarding water, a logical approach using the beakers provided can yield the desired result of 20 ml of water. Whether you use a combination of filling and topping up, recognizing the difference between beaker sizes, or following a straightforward step-by-step method, the key is to think through the problem logically and creatively.

For more creative solutions and insights into similar problems, click here to see another answer to this same question on the same forum.