Question

A Java book is comprised of two
sections core and advanced Java in the
ratio 7:2. How much of each type of
content will be needed to make a book of
450 pages?

Answer 1

Let  the common factor be⇒ x
then  core section has 7x pages and advance section 2x pages
As per problem 7x+2x=450
                       ⇒ 9x=450
                       ⇒   x=50
Core section 7x=350 pages
Advance Java 2x=100 pages

Answer 2

total pages=450
 ratio=7:2

no of pages of core Java req=(7/9)*450=350 pages 
no of pages of advanced Java req.=(2/9)*450=100 pages.