You need to find the volumes of the the two containers.
Then subtract the smaller volume from the larger volume.
Volume of Cylinder = pi * r^2 * h
radius = diameter/2
Container A:
radius = 38 ft/2 = 19 ft
Volume = pi * r^2 * h = 3.14159 * (19 ft)^2 * 19 ft = 21,548.2 ft^3
Container B:
radius = 32 ft / 2 = 16 ft
Volume = 3.14159 * (16 ft)^2 * 20 ft = 16,084.9 ft^3
Difference in volumes:
21,548.2 ft^3 - 16,084.9 ft^2 = 5,463.2 ft^3