What is the longest word in the dictionary?

In one of the popular batman series movie "Batman Forever", there was a riddle that goes like "Tear me off and then scratch my head and I was red then and now I am back. Who am I?

What has 13 hearts but no other organs?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?

Can you count the number of triangles inside a triangle?

I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time and space. What am I?

What has no start, end, or centre?

What has 88 keys?