Which number is less than 22,874? A. 2.18 x 10^4
B. 2.55 X 10^4
C.2.43 x 10^5
D. 1.78 x 10^6

Mary and roberto bought identical backpacks at different stores. mary's backpack originally cost $65 and was discounted 25%. roberto's backpack originally cost $75 and was on sale for 30% off on the original price. which backpack was the better buy?