John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

What is both possible and impossible at the same time?

The centre of the third figure is empty. What digit should fit inside?

What is the riddle which can be asked all day with a different correct answer each time.

Can you find out the remainder when 3^300 is divided by 5?

what does the below math rebus puzzle mean?

In the image given, you can find several triangles. Can you count them all?

What are the next two letters in the following series and why?
W A T N T L I T F S _ _

*Hint: Check Puzzle Title

10 people came into a hotel with 9 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the tenth guest to wait for a little with the first guest in room number 1. So in the first room, there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, ..., and the ninth guest to room number 8. Then he returned to room number 1 and took the tenth guest to room number 9, still vacant.
How can everybody have his own room?

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.