Find the volume of the cylinder to know how much liquid is in it:
volume of a cylinder = Pi x r^2 x height.
Volume = 3.14 x 60^2 x 210
Volume = 2,373,840 cubic cm
now to find the length of time divide total cubic cm by the drainage rate:
2,373,840 / 1099 = 2,160 hours
Answer: 2,160 hours