John was piloting a plane behind a car but was never able to overtake it. Why?

There are two guys standing face to face in a room. On a wall, there is a clock. One of those is a prophet. He tells the other guy that he will be stabbed in the back in five minutes.

Shocked to hear that, the other guy stares at the clock. Just after the five minutes, he is stabbed on the back. Can you tell what happened?

How can you spell "White of an egg" in one word?
Hint: I know you can spell coke, poke, and joke.

Why do we preferably have round manhole covers and not square ones?

You are provided with a grid (as shown in the picture). Can you fill the squares with numbers 1-8 in a manner that none of the two consecutive numbers are placed next to each other in any direction (vertically, horizontally or diagonally?)

Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

Take one out and scratch my head, I am now black but once was red. What am I?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

If an earthquake is 1 point higher on the Richter Scale than another earthquake which is actually 10 times stronger, how much stronger would an earthquake be if it was just half a point higher on the Richter scale?