One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

A girl has as many brothers as sisters, but each brother has only half as many brothers as sisters. How many brothers and sisters are there in the family?

Andrew sees a very rare bird named "Ruppell's vulture". Soon Andrew was dead. Can you explain the mystery, Mr. Sherlock?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

What has no start, end, or centre?

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

A dying old man wants to divide his entire land between his only two sons. Since his only wish is to treat them as equal as both of them have been too good to him, he wants to divide his land equally between them. The problem is that the land is significantly irregular in shape and thus there is no choice of cutting them into two equal halves.

Can you help him divide the land in a manner that both of his sons will be happy?

The more you take me, the more you leave me behind.
Who Am I?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

Give it food and it will live; give it water and it will die.