What has many keys but can’t open a single lock?

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

Which digit occurred maximum times between the number 1 and 1000?

I ask Joseph to pick any 5 cards out of a deck with no Jokers.

He can inspect then shuffle the deck before picking any five cards. He picks out 5 cards then hands them to me (Jack can't see any of this). I look at the cards and I pick 1 card out and give it back to Joseph. I then arrange the other four cards in a special way, and give those 4 cards all face down, and in a neat pile, to Jack.

Jack looks at the 4 cards i gave him, and says out loud which card Joseph is holding (suit and number). How?

The solution uses pure logic, not sleight of hand. All Jack needs to know is the order of the cards and what is on their face, nothing more.

What is the next number in this series?

4,12,84,3612....

If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

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

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

Something Extraordinary happened on May 6th 19778 at 12:34am what was that?

When can we add 2 to 11 and get 1 as the correct answer?