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 is the correct shadow of the bird?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

A sea diver is a real show-off. He showed everyone that he can hold his breath underwater for 15 minutes.

I went to the diver and told him that I can be underwater for double the time i.e 30 minutes.
He responded that he will give me 100$ if I would be able to do it. I won 100$.

What did I do?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

When I asked a girl's name she told me her name is the date '07/09/2001'.

I thought for a few seconds and then I got her name. Do you?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?