What is in seasons, seconds, centuries and minutes but not in decades, years or days?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

Can you find out which triangle will have a bigger area among the following?
1. A triangle with sides 300, 400 and 500
2. A triangle with sides 300, 400 and 700

Decode this picture on T-Shirt and tell what it says ?

Can you divide the below-given shape into four equal and identical pieces?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

Buy me, smell me or deliver me, I do not change.

Who am I?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

How can you throw a ball as hard as you can and have it come back to you even if it doesn't hit anything there is nothing attached to it and no one else catches or throws it.

What do you see in the given picture?