the pages of a book are numbered 1 to 300. Each leaf is 0.1 mm thick . If each cover is 0.25 mm thick. what is the thickness of the book​

30.5mm

Explanation:

There are 300 pages, so to find the number of pages we do 0.1mm*300 to get 30mm. There are two covers in the book (the front and the back). 0.25mm*2 = 0.5mm. To determine the total thickness of the book we do 30mm+0.5mm to get a total of 30.5mm

Your answer is 30.5mm.

15.5mm

Explanation:

there are 150 pages(one page has 2 sides so 300/2 = 150) and 2 covers

page's thickness is 0.1mm, cover's thickness is 0.25

so books thickness = 150*0.1+0.25*2 = 15.5mm