Question 485404
No wonder you have issues with this one, it is poorly stated.
The number of persons NOT reading "X and Y both" is 46,000.
It should read "How many persons read neither (no, nadda, zippo) paper?"
Ans: 3000.
Method: The number of papers read is X + Y = 51,000.
The number of persons reading them is less due to some of those persons being counted twice, so subtract them out.
51000 - 4000 = 47000 persons read at least one of those papers.
You are (or should have been) asked How many NOT readers? so that's all the people - those who read:
50000 - 47000 = 3000.
This is a case of the given answer helping to better word the question.