You Have a Five-Litre jug and a Nine-Litre Jug - Frequently asked Interview Puzzle

Riddles are questions that an interviewer asks to encourage a candidate to find a solution creatively to the problem. It helps an interviewer assess the ability of a candidate to apply logical thinking. Here is a commonly asked interview puzzle. 

Puzzle Details

You have a five-litre jug and a nine-litre jug. Your mother asks you to use these two jugs to measure one litre of orange juice. How would you do it?

Solution

To start with, first, fill the five-litre jug and then pour all the orange juice into the nine-litre jug.

This would leave with four-litre of space in the larger jug and 5 liter jug is empty.

Next, refill the five-litre jug and fill up the remaining portion of the nine-litre jug. As we know already that the space remaining in 9 liters jug was 4 liters, hence you have transferred 4 liters of orange juice from 5 liters jug and 1 liter of orange juice is still in 5 liters jug.

This way, we will have one-litre orange juice left in the five-litre jug, which was asked in the puzzle.

There can be other ways in which you can achieve the solution, but this is the most optimal solution.