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.

Can you decipher these quotes by Albert Einstein?
Blf xzm mvevi hloev z kilyovn lm gsv ovevo lm dsrxs rg dzh xivzgvw.

What is always in front of you but can’t be seen?

Can you write down eight eights so that they add up to one thousand?

In the picture given below, can you find out which digit will take place of the question mark?

You need to complete the maze by entering from the entrance marked below in the figure near the yellow circle, bottom left and leaving from the exit point near the green circle, bottom middle.

Rule of Game: You can move only by exchanging green and yellow circles.

Can you find the largest Three-digit number whose sum is 14 and whose square is less than 5,00,000?

What is the next number in this matchsticks series riddle?

4 fathers, 2 grand-fathers and 4 sons went to watch the movie.What is the minimum number of tickets they need to buy ?

I am white when I am dirty, and black when I am clean. What am I?