Answer:
175
Step-by-step explanation:
It is much easier if you use the unit rate, so we'll convert the first senta\ence into a ratio. 2 cubic feet:90lb. you need to get 1 cubic foot, so divide both sides my 2, 1 cubic foot:35 pounds. now, to get five cubic pounds(See where this is going?) you multiply both sides by 5. 5 cubic feet:175lb
(these idoits make you go back and forth in solving problems)