Answer:
8700 cubic inches, about 37.66 gallons
Step-by-step explanation:
The volume of a rectilinear space is the product of its length, width, and height. So, the volume of the tank is ...
V = L·W·H
V = (60 in)(14 1/2 in)(15 in) = 13050 in³
Since the tank is 2/3 filled, the volume of the water is ...
water volume = (2/3)V = 2/3 × 13,050 in³ = 8,700 in³
_____
There are 231 in³ in a gallon, so the number of gallons of water in the tank is ...
(8700 in³)/(231 in³/gal) ≈ 37.66 gal