See the attached picture for the complete answers to both questions:
Question A asked how much more water was required to fill the tank, so you need to calculate the full volume, then subtract 3/4 of the volume.
Question B, volume is cubed, so you need to cube the scale factor of 3. 3^3 = 27, so the larger tank is 27 times more.
Question C) Area is squared so you need to square the scale factor. Surface area would be 9 times more. 3^2 = 9
For the 2nd question, calculate the volume of each box and divide to find the number of boxes.
Then see the picture for total surface area for part B.