Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

What is the last thing you take off before bed?

Can you calculate the probability of getting a sum of six when a dice is thrown twice?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

It is raining today at 11:59 am. What is the probability of sunny weather after 72 hours?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?

Which is faster, Heat or Cold ? Explain.

Identify the 10 differences between the two given pictures.