A nut store sells cashews for four dollars per pound and peanuts for $1.50 per pound but at the end of the month the peanuts had not sold well so in order to sell 80 pounds of peanuts the manager decided to mix 80 pounds of peanuts with some cashews and sell the mixture for 350 per pound how many pounds of cashews should be mixed with the peanuts to ensure no change in revenue