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 have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

What's the only room from which no one can enter or leave

I taste better than I can smell. Who am I?

Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

Replace the question mark with the correct number below.