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?

Which flower has two lips?

John and Jenni are a married couple. They have two kids, one of them is a girl. Assume safely that the probability of each gender is 1/2.
What is the probability that the other kid is also a girl?

Hint: It is not 1/2 as you would first think.

Can you count the number of triangles in the given figure?

What is always in front of you but can’t be seen?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

How can you take 2 from 5 and leave 4?

What does this simple rebus mean?

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?