The list price of a book is $15. But if more than 12 copies are purchased, then the price per copy is reduced by $0.20 for every
copy above 12. That is, $14.80 per copy for 13 copies, $14.60 per copy for 14 copies, and so on. How much do you save by buying 24 copies than if you bought 2 sets of 12?
