How much water does it take to fill a 6 inch x 50 foot hose?

Volume of a cylinder = (pi) x (radius)2 x (length)

Radius = 0.5 inch

Length = 50 x 12 = 600 inches

231 cubic inches = 1 gallon

Volume = (pi) x (0.5)2 x (600) = 150 pi = 471.24 cubic inches = 2.04 gallons

That's the volume of the space inside the hose. We have no way to know

how much water is in it. It could be empty, half full of mud, ants, etc.