10 people came into a hotel with 9 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the tenth guest to wait for a little with the first guest in room number 1. So in the first room, there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, ..., and the ninth guest to room number 8. Then he returned to room number 1 and took the tenth guest to room number 9, still vacant.
How can everybody have his own room?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

A lion and its tamer are standing inside a cage that measures 1 unit in radius. Both of them can effortlessly run at the speed of 1 unit maximum.

1) Suppose the lion is hungry, will he be able to eat up the tamer?
2) If yes, how long can the tamer survive?

At a party, there are five people and a whole round cake lying at the centre of the table. Only four people will make a cut and take their piece and the last one will get the remaining piece on the table. How can they make sure that everyone gets a 1/5th of the piece?

You have a roll of cloth 1km long. You have a machine which cuts this roll into pieces of 10-meter-long cloth.

How long would it take for the machine to cut the roll if each cut took 4 secs?

What does below science rebus mean?

Ag Ag Ag
Ag SPOON Ag
Ag Ag Ag

In the image below, can you find the value of an angle(y)

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?