Question

a java book is comprised of two sections coremand 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

$7x+2x=450\\ 9x=450\\ x=50\\\\ 7x=350\\ 2x=100$

core(?) - 350 pages
advanced - 100 pages