Answer:
To find the number of days D it will take Tom to finish reading the book, we can use the following equation:
D = (215 - 11) / 6
Here, 215 is the total number of pages in the book, and 11 is the number of pages Tom has already read. The expression (215 - 11) gives us the number of pages Tom still needs to read.
Dividing this by the number of pages Tom reads each day (6) gives us the number of days it will take him to finish reading the book.
Simplifying this equation, we get:
D = 204 / 6
D = 34
Therefore, it will take Tom 34 days to finish reading the book if he reads 6 pages each day.