Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

What is full of holes but still holds water?

What is wrong in the below Picture?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

Find the next number in the series.
1 10 24 43 67 ?

Why Wine Glass Stem is so long?

I am an odd number. Take away a letter and I become even. What number am I?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

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.

How many times can you subtract the number two from the number fifty?