How many times do a clock's hands overlap in a day ?

I know a nine-letter word having only one vowel.
Do you ?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

A woman lives in a Tall building thirty-six floors high and 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?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

Find the next number in the sequence

1, 2, 6, 21, 88, __?

What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside.
The man said, "Oh! I am really sorry, I thought this was my room."
He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man.
What made her suspicious of that man? He might have been genuinely mistaken.

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

f you were running a race, and you passed the person in 2nd place, what place would you be in now?