When my father was 31 I was 8. Now he is twice as old as me. How old am I?

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?

Why do we preferably have round manhole covers and not square ones?

What four weights can be used to balance from 1 to 30 pounds?

Can you decipher the two rows to find the hidden word?

What common phrase is represented by the below lines

Easy going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Medium going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Tough going:
Weak, 'I can't do it, I'm staying!'
Tough, 'Let's get going.'

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?