The centre of the third figure is empty. What digit should fit inside?

Solve the rebus below.

Can you count the number of triangles inside a triangle?

Which is faster, Heat or Cold ? Explain.

If you read clockwise, you can form a word by inserting three missing letters in the picture given below. Can you do it?

John walks into the daily grocery shop and steals a $100 bill from the shop. An hour later John returns to the shop and buys some daily products for $40. John pays the owner the $100 bill and therefore the owner returns him $60.

How much money did the owner lose?

He digs out tiny caves and stores gold and silver in them. He also built bridges of silver and made crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs his help, yet many people are afraid to let him help them. Who is he?

Two trains start at the same time, one from Bangalore to Mysore and the other from Mysore to Bangalore. if they arrive at their destinations one hour and four hours respectively after passing one another, how much faster is one train running than the other?

What is the next number in this matchsticks series riddle?

What does below chemistry rebus means?