What word is pronounced the same if you take away four of its five letters?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

I know a nine-letter word having only one vowel.
Do you ?

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

In the below-given picture of a pretty girl, there is something wrong. Can you find out what it is?

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

A man plots the murder of his wife. His plan is full proof. Nobody saw them leaving their house. He stabbed her with a knife while driving. She died on the spot. He threw her body in a valley. He threw the knife carefully wiping his finger prints on a random garbage bin. Then he went back to his home and no one was watching him this time as well.

After an hour, he was called by the local police department who informed him that his wife was murdered. They asked him to reach the scene of crime immediately. But as soon as he arrived at the crime scene, he was arrested by them.

How did the police know that he himself is the murderer?

Imagine you are in a room with no windows or doors. How will you get out?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

There is so small cabin inside a deep forest.
All the forest burned out to worst possible but the inside of the cabin is still the same.
However all the person inside the cabin die.

How come ?