What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

What always comes into a house through the keyhole?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

A plane crashed between the border of Mexico and America. Where do you bury the survivors?

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?

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

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

I add 5 to 9 and get 2. The answer is correct, so what am I?

What 8 letter word can have a letter taken away and it still makes a word. Take another letter away and it still makes a word. Keep on doing that until you have one letter left. What is the word?

What Does this text mean:

important=important