Answer:
A.

Step-by-step explanation:
We have been given that a 300-page book is 10 inches long, 8 inches wide, and 3/4 inches tall. We are asked to find the volume of 100 pages of the book.
First of all, we will find the volume of whole book using volume of cuboid formula.
, where,
l = Length of cuboid,
w = Width of cuboid,
h = Height of cuboid.
Upon substituting our given values in volume formula we will get,



Since there are 300 pages in entire book and 100 is 1/3 of 300, so the volume of 100 pages will be the 1/3 of the volume of entire book.


Therefore, the volume of 100 pages will be 20 cubic inches and option A is the correct choice.