Geometry

Question Analysis
This question involves a combination problem with a specific inclusion condition.
The main focus is on adjusting the values of and based on the given condition and then using the combination formula to find the number of possible selections.

Key Concept Explanation
Since 3 particular books are already fixed to be in the selection, we only need to choose the remaining number of books from the remaining total number of books.
The combination formula is still applicable for this adjusted situation.

Step - by - Step Solution
Since 3 books are already included, we need to choose more books from the remaining books.
So, and .

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