Geometry

Question Analysis
This question is about applying the combination formula for non - repetitive selection.
The main point is to correctly determine the values of (total number of books) and (number of books to be borrowed) and then use the formula to calculate the number of combinations.

Key Concept Explanation
The formula is used when we need to select items from distinct items without repetition, and the order of selection has no impact. Here, and .

Step - by - Step Solution
First, find the factorials:

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