A girl has as many brothers as sisters, but each brother has only half as many brothers as sisters. How many brothers and sisters are there in the family?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

There is a circular car race track of 10km. There are two cars, Car A and Car B. And they are at the exact opposite end to each other. At Time T(0), Both cars move toward each other at a constant speed of 100 m/seconds. As we know both cars are at the same speed they will always be the exact opposite to each other.
Note, at the center, there is a bug which starts flying towards Car A at time T(0). When the bug reaches car B, it turns back and starts moving towards the car A. The speed of bug is 1m/second. After 5 hours all three stop moving.
What is the total distance covered by the bug?

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

which number am I?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

A Japanese ship is sailing in the Indian Ocean. The captain of the ship feels tired and decides to take shower to be rejuvenated. He goes to take the shower after keeping his diamond-studded Rolex watch and gold chain on the table.
When he comes back after 15 minutes, he finds them missing. There are 4 crew members on the ship and he calls them one by one to ask them what they were doing in that duration.

Following are the answers:
1. Crew 'A' who is the cook replies that he was cooking mutton for the crew members.
2. Crew 'B' who is a housekeeper tells that he was sleeping in his room.
3. Crew 'C' who is the engineer says that he was checking on the generator.
4. Crew 'D' who is another housekeeper says that he was correcting the hoisted flag that was put upside down.

It took only a couple of seconds for the captain to find the thief. Can you find the thief too?

You are given four tennis balls and asked to arrange those balls in a manner that the distance between each one of them is exactly equal. How will you do it?

What is the Surname of Barbie Doll?

What does this rebus means ?

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?