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

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

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 mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?

Yesterday I fell from 30 feet high ladder but I don't get hurt. Why?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

There is a square piece of paper with a hole that is denoted by the circle on the top right side in the given picture. You have to cut the paper in a manner that it forms two and only two separate pieces of paper and then rearrange the pieces in a manner that the holes come in the centre of the paper.

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 ?

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?