ms. dasilva needs to refill her stock of post-its. at the store, she finds two option: staples an 18-pack which costs $15.30. office max a 4-pack which costs $3.93. which store offers the better buy? Ms.dasilva wants to purchase 72 packs of post-its. How much will she save if she chooses the cheaper option? staples wants to offer a 25% discount for teachers. If ms. dasilva purchases 54 packs of pst-its at staples, how much will she pay? show and explain your work.