Felix is chopping down trees in his backyard. For every 13 trees he chops down he needs to get his axe resharpened. It cost him $5 to sharpen his axe. If he spends $35 on axe sharpening, at least how many trees has he chopped down? Think carefully first, then make a decision:
He has sharpened in 7 times because 35 / 5 = 7. He has chopped down 91 trees because 7 x 13 = 91. So, the answer is 91.