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.

What can you hold in your right hand, but never in your left hand?

Solve the rebus riddle in the picture below.

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

Find the missing number in the image below.

I am quite hot but become too cold if you remove the first two letters. What am I?

Solve the following series:
AZ, GT, MN, __, YB

John was driving a bus and got stuck when passing through an underpass. Then came Jacob with a needle and got the bus out of the underpass.

What did the boy do?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

The two towns are exactly 100 km apart. John leaves City A driving at 30 km/hr and Jacob leaves City B half an hour later driving at 60 km/hr. Who will be closer to City A when they meet?