• # Solve this if you can! - The best puzzle I came accross :)

This question was asked by an ethical hacking company which visited my college for campus recruitment! This question blowed everybody's brains. None were able to answer it. Finally, we were dumbstruck after listening to the answer!!!

The question goes as follows:

There are 5 pill (tablet) bottles. Each bottle has 10 pills. Each pill weighs exactly 10 grams. Due to some defect in manufacturing, the pills in one of the bottles were underweighed by 1 gram (i.e. each pill of that defected bottle, weighed only 9 grams).

Now, the task is to find which bottle has the defective pills, BY MEASURING THE WEIGHT ONLY ONCE.

Lets see who is smart enough to answer this! :)
• Hi Vijay,
This is easy to find. Mark the bottle as 1,2,3,4 and 5. First take 1 pill from the first bottle and 2 pill from the second bottle and so on. So from 5 bottle you have taken 15 pills overall. Now calculate the weight of this 15 pill. If it is 4.9g then the defective pills is from first bottle.

4.8 g - 2nd bottle [(2*.9)+3]
4.7 g - 3rd bottle [(3*.9)+2]
4.6 g - 4th bottle [(4*.9)+1]
4.5 g - 5th bottle [(5*.9)+0]

• Hi Venkata Kumar,

Your solution was correct :) You must have picked it up from some friend of your's na? :)

Excepting for one fact; I said each pill weighs 10 grams. According to your solution, you had taken each pill to weigh 1 gram. Only that confusion.

• I got this answer from one of the training and placement program conducted in my college. Ya I accept that it was not my own answer. I calculated 1g instead of 10g and .9g instead of 9 gram.

• Great :)
Try the other problem i posted today!