what's the probability of getting a king or a queen from a pack of 52 cards?

A woman lives in a skyscraper thirty-six floors high and is served by several elevators which stop at each floor going up and down. Each morning she leaves her apartment and goes to one of the elevators. Whichever one she takes is three times more likely to be going up than down. Why?

When it is alive we sing, when it is dead we clap our hands. What is it?

It begins where the time ends.
Its second is an expression of surprise.
Its third is a question.
Its fourth is urinate.
It ends with a drink.

Which country it is?

Can you name an animal whose killing cannot be performed without spilling your own blood?

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

What can jump higher than a building?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

There are 2 cops parked along a one-way street looking for traffic violations. They spot a taxi driver going in the wrong direction, yet they do nothing.

Why?