An english book is comprised of two sections, literature and grammar, in a ratio of 3: 2. how much of each type of content will be needed to make a book of 150 pages

Since your total for the English book is 5, you make a ratio of

5:150

to make 5 equal 150, you multiply by 30. So if you multiply 3 by 30, you get 90, and 2 by 30 you get 60

60+90=150

new ratio-  90:60

or 90 pages of literature and 60 pages of grammar