Can you name some countries which do not have the alphabet 'A' in them?

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

You bought me for dinner but never eat me. What am I?

Replace the question mark with the number below given a simple math problem.

What do you think with the below Picture ?

Move four matchsticks to the below square to form three squares?

If six children and two dogs were under an umbrella, how come none of them got wet?

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

which number am I?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?