Current location - Quotes Website - Signature design - There are 100 books in the library. You need to sign books when you borrow them. It is understood that in this 100 book,
There are 100 books in the library. You need to sign books when you borrow them. It is understood that in this 100 book,
"A ∩ C" refers to the total number of books signed by both parties;

"A ∩ B" refers to the total number of books signed by both parties;

"B ∩ C" refers to the total number of books signed by both parties;

"A ∩ B ∩ C" is the total number of books signed by Nail, B and C simultaneously.

It can be concluded that the total number of books borrowed by A, B and C is: A+B+C-(A ∩ B+A ∩ C+B ∩ C)+A ∩ B ∩ C.

Because the first six items are quantitative, the bigger the "A ∩ B ∩ C", the more books three people borrow. Because A ∩ C is 25, A ∩ B ∩ C is 25 at most. Substituting the above formula, we can see that the total number of books borrowed by A, B and C is 67, and the total number of books not borrowed by A, B and C is at least 33.