1. Calculate the volume in cubic inches:
* Volume = Length x Width x Height
* Volume = 18 inches x 7 inches x 15 inches
* Volume = 1890 cubic inches
2. Convert cubic inches to gallons:
* There are 231 cubic inches in one gallon.
* Gallons = Cubic inches / 231
* Gallons = 1890 cubic inches / 231 cubic inches/gallon
* Gallons ≈ 8.18
Therefore, a fish tank with dimensions of 18x7x15 inches holds approximately 8.18 gallons.