Tank Filling Riddle

A large water tank has two inlet pipes (a large one and a small one) and one outlet pipe. It takes 3 hours to fill the tank with the large inlet pipe. On the other hand, it takes 6 hours to fill the tank with the small inlet pipe. The outlet pipe allows the full tank to be emptied in 9 hours.

What fraction of the tank (initially empty) will be filled in 0.64 hours if all three pipes are in operation? Give your answer to two decimal places (e.g., 0.25, 0.5, or 0.75).




Similar Riddles

I know a 5-digit number having a property that With a 1 after it, it is three times as large as it would be with a one before it.

Guess the number?

Asked by Neha on 06 Apr 2025


It belongs to you, but other people use it more than you do. What is it?

Asked by Neha on 19 Feb 2022

Spot the 3 Differences in the given Picture.

Spot the 3 Differences

Asked by Neha on 20 Sep 2026


I have an apple tree , number of apple in this tree get doubles every week.

On 30th week , the tree gets completely filled with apples :-)



Can you tell me , on what week does my tree is half covered with apples ?

Asked by Neha on 28 Feb 2021

The king of Octopuses has servants who have six, seven or eight legs. The distinguishing characteristics of the servants is that the one with seven legs always lie but the one with either six or eight legs speak the truth always.

One day, four servants meet and converse:

The black one says, 'We have 28 legs altogether.'

The green one says, 'We have 27 legs altogether.'

The yellow one says, 'We have 26 legs altogether.'

The red one says, 'We have 25 legs altogether.'


Can you identify the colour of the servant who is speaking the truth?

Servants with multiple legs

Asked by Neha on 09 Apr 2021

The UN Security Council has how many member states?

a) 15
b) 10
c) 20
d) 25

Asked by Neha on 09 Sep 2026


A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside. The man said, "Oh! I am really sorry, I thought this was my room." He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man. What made her suspicious of that man? He might have been genuinely mistaken.

Asked by Neha on 27 Jan 2024

Can you find a five letter word that is left with only two letters if one is removed?

Asked by Neha on 20 Jul 2021

Look at the picture and find out which square is not linked with any of the other squares.

Squares not Connected

Asked by Neha on 31 Mar 2024


We are a group of eight brothers. We consider the weak, yet we protect the king in every battle. If we move ahead, we never turn back. Who are we?

Asked by Neha on 15 Feb 2026

Hot Articles

Amazing Facts

No Solution

In 2007, a puzzle was released and $2 million prizes were offered for the first complete solution. The competition ended at noon on 31 December 2010, with no solution being found. Wiki