The object with more volume is the inflated balloon
Explanation:
Volume is about how much space an object or material occupies; in this context, if the inflated balloon has the double size of the bag of marbles then the balloon has more volume because this is occupying more space.
Moreover, the volume should not be confused with other factors such as mass or weight because it is likely the marbles weight more but this does not imply the marbles have more volume. Also, the balloon contains gas and gases tend to expand and occupy more space, which does not occur with solids such as marbles because these have a defined volume.
