If you say my name, I will no longer exist. What am I?

If 21x = 79x, what is the value of x?

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?

Two boys were admitted to a school. When the headmaster asks them about their parents, they tell him that they have same parents (father and mother). On further inquiry, it turns out that they both share the same date for their birthday.

"Are you twins," ask the headmaster.
"No," replies the boys.

Is it possible?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

Which is heavier: a ton of bricks or a ton of feathers?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

Solve the equation by replacing the alphabet with numbers.

MOM + MOM + NO = BOOK=

In a town, there are four houses located at different distances from each other. Following are the distances:

The third house is 60 meters apart from the first house.
The fourth house is 40 meters apart from the second house.
The third house is 10 meters nearer to the fourth house than it is to the second house.

Can you find out the distance between the fourth and the first house?