If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

An evil man kidnapped someone and made them take one of two pills. One was harmless, but the other was poisonous. Whichever pill the victim took, the kidnapper took the other one. The victim took their pill with water and died. The kidnapper survived. How did the kidnapper get the harmless pill?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

What is the next number in this matchsticks series riddle?

There are forty elephants and they have forty-fore heads. How can this be possible?

I am a word that begins with the letter “i.” If you add the letter “a” to me, I become a new word with a different meaning, but that sounds exactly the same. What word am I?

Imagine you are in a room with no windows or doors. How will you get out?

Rearrange the letters in "new door" to make one word.