What does this rebus puzzle means ?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

When I asked a girl's name she told me her name is the date '07/09/2001'.

I thought for a few seconds and then I got her name. Do you?

What always comes into a house through the keyhole?

What does this rebus mean?

O
N
C
E
TIME

Three ants are sitting at the three corners of an equilateral triangle. Each ant starts randomly picks a direction and starts to move along the edge of the triangle. What is the probability that none of the ants collide?

This is a simple one. You just have to count the number of Fs in the given sentence.

Finished Files are the result of years of scientific study combined with the experience of years.

How many did you count?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

Can you find the missing number in the third row?
35 20 14
27 12 18
5 2 ?

Can you make the number 24 by utilizing the numbers 1, 3, 4 and 6? You must use one number only one time and you can use mathematical operation symbols anytime anywhere.