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?

While preparing the table for dinner, wife came up with an idea to tease his mathematician husband. She asked her husband to pick nine toothpicks and make ten without breaking any toothpick.

The husband was also smart and did it within seconds. How ?

The more of this there is, the less you see. What is it?

What is the fastest way to double your money?

In the figure that has been attached to this question, each digit represents a digit. The similar letters carry the same integer value. Can you expose the original digits?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

Forwards I am heavy, backward I am not. What am I?

A sundial has the fewest moving parts of any timepiece. Which has the most?

Make the seating arrangement of 10 children in such a way that there are 5 rows with 4 children in each row.