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

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

We have four gears with below features=> Both Gear A and D has 60 teeth=> Gear B has 40 teeth=> Gear C has 20 teeth=> Every two minutes, Gear B makes 25 full turns.What is the relative speed of Gear A and Gear B?

Can you find a five letter word that is left with only two letters if one is removed?

If an electric train is travelling south, then which way is the smoke going?

This is a most unusual paragraph. How quickly can you find out what is so unusual about it? It looks so ordinary, you'd think nothing was wrong with it. Actually, nothing IS wrong with it. But it is not as ordinary as you might think. If you think about it for a bit, you will find out why it is truly so unusual. So what is it? What is so unordinary about this paragraph?

What came first, the chicken or the egg?

Jack and Joseph are well-known golf rivals. One Day during a match, they were level at a score of 30. Jack hit a bad shot and Joseph added 10 to his score. Joseph then hit an awesome shot and he won the game.

How ?