1/3bag = 1 day 1/3bag x ? days = 1 1/3 bags 1/3d = 1 1/3 or 4/3 divide each side by 1/3 or multiply each side by its inverse 3/1 1/3 * 3/1 d = 4/3 * 3/1 the 1’s and 3’s cancel each other out on the left and the 3’s cancel each other out on the right. You are left with d = 4 The food will last 4 days.
