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.

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

If an electric train is travelling south, then which way is the smoke going?

Can you quickly find which two matchstick figures are identical?

What four weights can be used to balance from 1 to 30 pounds?

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

The more you take me, the more you leave me behind.
Who Am I?

Decode below rebus
D
N
A
T
S , D

A tourist visits a small town for his research. While in the town, he decides to get a haircut. Since the town is quite small, there are only two barbers in the town � one on the North Street and one on the South Street. The barbershop on the North Street is a mess and the barber has a weird and pathetic haircut. While the barbershop at the South Street is pretty tidy and the barber as well has an impressive haircut.

Which barbershop will the tourist visit for his haircut and why?

It is deaf, Dumb and Blind!!!

Still, always tells the truth. What is it?