Which number should replace the question mark?

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

He runs but never walks. Murmurs, but never talks. Has a bed, but never sleeps. And has a mouth, but never eats?

Can you guess the name of the month by looking the below rebus ?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

On a special event at the prison, 5 prisoners John, Jacob, Krist, Tang, and Dang given a chance to go to a sauna and can bring one thing with them.

Following are the things that the prisoners bring with them.
John: A soda
Jacob: Thermos
Krist: Book named "How to kill"
Tang: A Walkman
Dang: Harmonica

Since it is a Sauna, no one can see each other. After a while When the steam is switched, Tang was found dead and there was blood all around.
J Bond was called and he instantly come to know who can be the murderer. How?

Two trains start at the same time, one from Bangalore to Mysore and the other from Mysore to Bangalore. if they arrive at their destinations one hour and four hours respectively after passing one another, how much faster is one train running than the other?

No matter how little or how much you use me, you change me every month. What am I?