Can you replace the question mark with the correct number?

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?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

John is on an island and there are three crates of fruit that have washed up in front of him. One crate contains only apples. One crate contains only oranges. The other crate contains both apples and oranges.

Each crate is labelled. One reads 'apples', one reads 'oranges', and one reads 'apples and oranges'. He know that NONE of the crates have been labeled correctly - they are all wrong.

If he can only take out and look at just one of the pieces of fruit from just one of the crates, how can he label all of the crates correctly?

Can you name some countries which do not have the alphabet 'A' in them?

Can you place six X (crosses) in below board without making three in a row in any way ?

What has many teeth, but cannot bite?

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

If,

6 / 7 = 2
3 / 9 = 7
8 / 2 = 6

Then

4 / 5 = ?

What 5-letter word typed in all capital letters can be read the same upside down?