I’m tall when I’m young, and I’m short when I’m old. What am I?

If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

I’m tall when I’m young, and I’m short when I’m old. What am I?

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

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.

Bopanna was working on a murder case when he received a message about the location of the murder weapon.
The message was encrypted as below.

"deb mitciv eht edisni neddih si nopaew redrum ehT"

Tell me the location of the murder weapon.

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

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

How can you leave a room with two legs and return with six legs?