About 7.5 gallons of water will fill up 1 cubic foot of space. how many gallons of water will fill a goldfish pool shaped like the prism shown

Well, since there is no image I am unable to say the exact volume. But here is the volume formula-
V=L times W times H
*V=volume W=width H=height
and you don't actually have to write times you can do the symbol.

Example- if I had a rectangular prism of the width being 5 cubes, the length 8 cubes, and the height 7 cubes(following how many gallons are in a cube 7.5) I would the use my formula. V=LWH- 8 times 7= 56 56 times 5=280 280 times 7.5= 2100
V=2100 (that is your answer reply If you didn't mean the volume or you don't get it)

Iknow one of the answers is a and maybe b but not 100% sure about b