What number should come in place of the question mark below?

Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?

What is red and smells like blue paint?

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

Out of four images which one is the odd one out?

Before Mount Everest was discovered, what was the highest mountain in the world?

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

Can you solve the maths in the below-given picture equation?

Replace the question mark with the number below given a simple math problem.