Answer:
750 books
Step-by-step explanation:
Let there be "x" number of books in the 3rd room
Now,
2nd room has 3 times as 3rd room, so we can write:
Second Room = 3x
Also, there are 1960 MORE books in 1st room than 2nd room, so we can write:
First Room = 3x + 1960
In total there are 7210 books in all three rooms, thus we can write:
First Room + Second Room + Third Room = 7210
Now, replacing the first 2 equations in this, we get:
3x + 1960 + 3x + x = 7210
Solving for x:
"x" is indeed what we are looking for. Thus,
There are 750 books in the third room