Answer:
She needs 9 bags (8.75 specifically) to fill the space around the photo box.
Explanation:
Volume of rectangular box = length x width x height = 12.5 in x 4.2 in x 12.5 in = 656.25 cubic inches
Subtracting the volume of the photo box from the volume of the rectangular box, we get:
The volume of packing material = Volume of the rectangular box - Volume of the photo box
Volume of packing material = 656.25 cubic inches - 0 cubic inches = 656.25 cubic inches
Therefore, the number of bags needed is:
Number of bags = Volume of packing material / Volume of one bag
Number of bags = 656.25 cubic inches / 75 cubic inches per bag = 8.75 bags
Rounding up to the nearest whole number, Sasha needs to buy 9 bags of packing material to fill the space around the photo box.