In how may ways can 15 identical books of mathematics and 12 identical books of physics be placed in a row on a shelf so that tow books of physics may not be together ?

Explanation

To solve the problem of arranging 15 identical mathematics books and 12 identical physics books on a shelf such that no two physics books are adjacent, we can follow these steps:

### Step 1: Arrange the Mathematics Books
First, we need to arrange the 15 identical mathematics books. When we place these books on the shelf, they will create spaces where the physics books can be placed.

- **Arrangement**: M M M M M M M M M M M M M M M (15 M's)
- **Spaces Created**: When we arrange 15 mathematics books, they create 16 spaces (one before each book, one after the last book).

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