What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

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?

I purchased an awesome ice cream cone having 5 different flavour scoops.
Five flavours are pistachio, mint-chip, strawberry, marshmallow, and raspberry

I will give u some clues so that you can figure out the order of flavours from bottom to top.
1. The bottom flavour of the cone has 10 letters.
2. The marshmallow scoop is between the pistachio and the mint-chip scoop.
3. marshmallow is the raspberry scoop but below the mint-chip scoop.

So can you figure out the flavour of ice cream in order from bottom to top?

I had an infinite supply of water and 5 litres and 3 litres jars.

How would you measure exactly 4 litres in the least number of steps?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

If you read clockwise, you can form a word by inserting three missing letters in the picture given below. Can you do it?

A boy was at a carnival and went to a booth where a man said to the boy, "If I write your exact weight on this piece of paper then you have to give me $50, but if I cannot, I will pay you $50." The boy looked around and saw no scale so he agrees, thinking no matter what the carny writes he'll just say he weighs more or less. In the end the boy ended up paying the man $50. How did the man win the bet?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

Two men play a dice game involving roll of two standard dice. Man X says that a 12 will be rolled first. Man Y says that two consecutive 7s will be rolled first. The men keep rolling until one of them wins.

What is the probability that X will win ?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?