Can you count the number of matches in the picture below ?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

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

You are confined in a room and given two metal rods. Out of these two rods, one is magnet and the other is the iron rod. They look starkly similar. You don't have any other metal object in the room.

How will you decide which one of those is magnet?

Solve below rebus puzzle?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

If a shopkeeper can only place the weights on one side of the common balance. For example, if he has weights 1 and 3 then he can measure 1, 3 and 4 only. Now the question is how many minimum weights and names of the weights you will need to measure all weights from 1 to 1000? This is a fairly simple problem and very easy to prove also.

Can you find the hidden animal in the picture below?