What does this rebus riddle means ?

In the picture given below, can you find out which digit will take place of the question mark?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

I am 5 letters long.
My first two tell you who I am
My first 3 could be a medicine
My last three reversed could be a young boy.
My 4th, 3rd and 2nd in that order could be a fruit drink.
If you have me you may hang me round your neck
WHAT AM I ?

Can you solve the rebus below?

What occurs twice in a week, once in a year but never in a day?

A devotee visits 9 temples when he visits India. All these nine temples have one thing in common - there are 100 steps in every temple. The devotee puts the Re.1 coin after climbing up every step. He does the same while climbing down every step. At each temple, the devotee offers half of his money from his pocket to god. In this way, his pocket becomes empty after he visits the 9th temple.

Can you calculate the total amount he had initially?