if an aquarium is 5" x 10"x7" how much water can it hold using the scale 1"=6"

You are given the volume to be

5 inches times 10 inches times 7 inches, which = 350 inches^3.

Volume in measured in cubic units, which is the reason for exponent 3.

You are NOT too clear with the scale given as 1 inch = 6 inches.

Do you want to convert to feet, cm, meters, what exactly?

The volume is 350 inches of water that the tank can hold.

Maybe you meant to type 1 foot = 6 inches as a scale, which makes more sense.

Get back to me and we can then take it from there.