Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

What do you think with the below Picture ?

Replace the question mark with the correct number.

2 + 2= 4
3 + 3= 18
4 + 4= 48
5 + 5= ?

A boy purchased a book from a bookkeeper and gave him $100.
The cost of the book is $50 but the bookkeeper has no change, so he gets the change from the next shop and returns the boy his $50.

After some time the next shopkeeper came with the $100 note and told the bookkeeper that the note was a fraud, so he took the money back.

How much loss did the bookkeeper face?

A train full of passengers goes through a tunnel. When the train comes out from the other end, there is no single person on the train.

How did it happen?

After teaching his class all about Roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The teacher's only stipulation was that the pen could not be lifted from the paper until the line was complete.