Answer:
There are 1500 non fiction books and 500 fiction books currently in the store.
Step-by-step explanation:
Given:
Total Number of books = 2000
Let the number of fiction books be 'x'.
Now given:
There are 3 times as many non-fiction books as fiction books.
Number of non fiction books = 
We need to find the number of non-fiction and fiction books.
Solution:
Now we know that;
Total Number of books is equal to sum of the number of non-fiction and fiction books.
framing in equation form we get;

Dividing both side by 4 we get;

Number of fiction books = 500
Number of non fiction books = 
Hence There are 1500 non fiction books and 500 fiction books currently in the store.
Answer:
The average speed of the plain was 800 miles/h
Step-by-step explanation:
The

symbol means intersection, so everything that is in both sets, and the

symbol means union, so the two sets combined.


So the answer is A.