Two guards were guarding the camp.Guard-1 was looking towards the south to make sure no threat is coming from the road.Guard-2 was looking at the north to make sure no threat is coming from the top. Suddenly Guard-1 ask the Guard-2 why he is smiling?How Guard-1 knows that Guard-2 is smiling?

Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be ?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

Find The Missing Number In the Sequence.
6 25 64 ? 32 1

There are three light switches outside a room. One of the switches is connected to a light bulb inside the room.
Each of the three switches can be either 'ON' or 'OFF'.

You are allowed to set each switch the way you want it and then enter the room(note: you can enter the room only once)

Your task is to then determine which switch controls the bulb?

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

1 dollar = 100 cent
= 10 cent x 10 cent
= 1/10 dollar x 1/10 dollar
= 1/100 dollar
= 1 cent

=> 1 dollar = 1 cent

solve this tricky problem?

What's the only room from which no one can enter or leave

using four eights (8) and a one (1) and one mathematical symbol , create the number 100