What is next number in the pattern below:

131 517 192 123 ?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

How many triangles do you see in the picture puzzle below?

Why do people go to bed?

The dirtier I get, the whiter I look. Who am I?

Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water.

How many frogs are there on the log at this moment?

You have to fill the below given grid in a manner that every row and column contains the digits 1 to 6. Also, make sure that the squares that are connected with each other must contains the same digit.

Which letter of the alphabet has the most water?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?