Question

There are 5 people in the room you entered in a room with its gun and kill 4 people how many people left in the room

Answer 1

5 people left in room because it's written that I killed 4 people but it's not mentioned that in room ...

Answer 2

To come means you were at a place and went over to this place.

This means that there was originally 5 people in a room. You came into the room and murdered 4 of them.

‘How many’ refers to how many of those people in that room originally are left. 

You won't count yourself because you weren’t there originally.

So that means the answer to your question is 1 person.