math
posted by Anonymous on .
A high school has designed he yearbook. A company charges $900 to assemble the master copy and $42 to make additional copies. The total selling price depends on how many copies are made. Write a funtion rule and determine how much will the school save on each book by ordering 600 instead of 200?

looks like
Cost = 900 + 42n , where n is the number of books
for 600 books cost = 900+42(600)
= 26100
cost per book = 26100/600 = 43.50
for 200 books cost = 900 + 200(42)
= 9300
cost per book = 9300/200 = 46.50
so how much do they save per book?