A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

Which digit occurred maximum times between the number 1 and 1000?

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

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

which number am I?

If a boy blows 18 bubbles,
Then pops 6 eats 7 and then
He pops 5 and blows 1.
How many are left?

Which number should replace the question mark?

A container contains 100 eggs. They can be either fresh or rotten. What is sure is the fact that there is at least one fresh egg in that container.

If you are asked to pick two eggs randomly from the container, at least one of them will be rotten.

Can you calculate how many eggs in that container are fresh?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

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