<span>With the bag having 4/5 lb currently in it, this can be translated to 16/20 lb. Maria wants to scoop out sand until the bag has 1/2 lb, which is 10/20 lb. The scoop that Maria uses is 1/20 lb, so using the equation of 16-10 = 6, Maria can get 6 scoops of sand before the bag contains 1/2 lb.</span>