Answer:
4 bags, or 4 1/4 bags
Explanation:
change 3 1/2 into a improper fraction, then change it to have a common denominator as 3/4. the expression would then be (14/4 + 3/4) divided by 1/2. 17/4 divided by 1/2 is 4 1/4. it would depend if they meant to fill the whole bag.