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.

By using all numbers, i.e. 123456789 and subtraction/addition, operators number 100 can be formed in many ways.
Example: 98 + 7 + 6 - 5 - 4 - 3 + 2 - 1 = 100

But if we add a condition use of the number 32 is a must. Then there are limited solutions.
One of such solution is: 9 - 8 + 76 + 54 - 32 + 1 = 100

Can you tell me any other solution?

Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

You Are Highly Attentive If You Can Spot A Hat In This Bathroom In 9 Seconds!

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

Where do you go to learn how to make ice cream?

Once while in his court, King Akbar asked Birbal to write something on a wall that makes one sad when read in good times and makes one happy when read in sad times.

He took only a few moment and wrote something that fit the requirements. What did he write?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Can you name an animal whose killing cannot be performed without spilling your own blood?