Why is the Hole below a Lock?

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).

How is the moon similar to a dollar?

There are forty elephants and they have forty-fore heads. How can this be possible?

A mules travels the same distance daily.
I noticed that two of his legs travels 10km and the remaining two travels 12km.
Obviously two mules legs cannot be a 2km ahead of the other 2.

The mules is perfectly normal. So how come this be true ?

What does the below image rebus riddle means ?

Below toothpicks/matchsticks indicate the group of fishes moving from west to east direction. Can you make them move from east to west by just moving three toothpicks/matchsticks?

How many triangles are there on the puzzle below?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

I am soft and cuddly that soothe your heart. But, If you pick my last name I am going to tear you all apart. Who am I?