How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

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?

What is black when you buy it, red when you use it, and gray when you throw it away?

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

I have a head like a cat and feet like a cat, but I am not a cat. What am I?

Which is faster, Heat or Cold ? Explain.

A man hijacks an aeroplane transporting both passengers(8 of them) and valuable cargo. After taking the cargo, the man demands nine parachutes, puts one of them on, and jumps, leaving the other eight behind. Why did he want eight?

In the attached figure, you can see a chessboard and two rooks placed on the chess board. What you have to find is the number of squares that do not contain the rooks. How many are there?

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?

How do you go from 98 to 720 using just one letter?