Which number should replace the question mark?

What is both possible and impossible at the same time?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

Can you find the odd number in the following?

2716, 4135, 5321 and 7145

John, a 5-year-old boy, was really fond of the chocolates. He asked his Mother to give him some money to buy his favourite chocolates. His Mother gave him $45. He went to the shopkeeper and asked, "How much is one chocolate for?". The shopkeeper said $3 for one chocolate. Also, if you give me the wrappers of three chocolates, I will give you one for the exchange.
In total, how much chocolate could John eat?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

I throw two dice simultaneously.

What is the probability of getting a sum as 9 of the two numbers shown?

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

A girl rode into a tourist spot out of the city on Thursday. She loved the place and decided to stay for a few days. She stayed for four days and then she left for back home on Thursday.

How can this be possible?