“Can you solve this puzzle asked in companies like Tredence and Amazon?”
Imagine this scenario: You have two hourglasses: one measures 4 minutes, and the other measures 7 minutes. Your task is to measure exactly 9 minutes.
It’s a classic brain teaser that tests logical thinking and problem-solving skills. If you want to pause and try solving it yourself first, go ahead!
Breaking Down the Solution
If you’re ready, let’s dive into the step-by-step solution:
Step 1: Start Both Hourglasses
Turn over both the 4-minute and 7-minute hourglasses simultaneously. Time begins now!
- Time elapsed: 0 minutes
Step 2: Flip the 4-Minute Hourglass
When the 4-minute hourglass runs out, flip it immediately.
- Currently, 4 minutes have passed, and 3 minutes remain in the 7-minute hourglass.
- Time elapsed: 4 minutes
Step 3: Flip the 7-Minute Hourglass
When the 7-minute hourglass runs out, flip it immediately.
- Now, 7 minutes have passed, and there is 1 minute remaining in the 4-minute hourglass.
- Time elapsed: 7 minutes
Step 4: Flip the 7-Minute Hourglass Again
When the 4-minute hourglass runs out again, flip the 7-minute hourglass immediately. This adds one more minute.
- At this point, 9 minutes will have passed by the time the 7-minute hourglass runs out again.
- Time elapsed: 9 minutes
Why Does This Work?
The key to solving this puzzle lies in:
- Resetting the timers strategically to align their cumulative time measurements.
- Leveraging the difference between the hourglass times (4 and 7 minutes) to reach the target.
This is why such puzzles are often used in job interviews — they showcase your ability to break down complex problems and think logically under pressure.
Did You Solve It?
Did you figure it out on your own? Whether you cracked it or learned something new, puzzles like this are a great way to sharpen your mind.
Follow for more brain teasers, and let us know how long it took you to solve this one in the comments below
