If eleven plus two equals one, what does nine plus five equal?

Rearrange the letters in "new door" to make one word.

A mules travels the same distance daily.
I noticed that two of his legs travels 10km and the remaining two travels 12km.
Obviously two mules legs cannot be a 2km ahead of the other 2.

The mules is perfectly normal. So how come this be true ?

Can you name four days which start with the letter 'T'?

I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

What number should come in place of the question mark below?

It is a 5 letter word if you take away first letter it is something you get from sun, if you remove second letter you will get something to eat, if you remove third letter you get a word you use in pointing at and if you remove the fourth letter you get something to drink. What is it?

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?

You are a cab driver who pools passengers. You pick 3 people from a destination and drop 1 after an hour. 2 people climb aboard at the same time and you drop 3 at the next destination. After some time, you pick 2 passengers only to drop 1 after a short distance where 3 more passengers climb up the cab. You leave the rest of the passengers one by one to their destination and then come back home.

Can you tell the eye color of the cab driver?

Replace the question mark with the correct number.