Answer:
To calculate the minimum thickness of the book, we need to add the thickness of the front and back covers to the thickness of all the pages.
Step 1: Calculate the thickness of the front and back covers:
2 * 0.9 mm = 1.8 mm
Step 2: Calculate the thickness of all the pages:
400 pages * 0.13 mm/page = 52.0 mm
Step 3: Add the thickness of the front and back covers to the thickness of all the pages:
1.8 mm + 52.0 mm = 53.8 mm
Answer:
The minimum thickness of the book is 53.8 mm.