Radius of green vessel = 4/2 = 2
Radius of red vessel = 6/2 = 3
Radius of blue vessel = 8/2 = 4

Volume of green vessel on its own = π × 2² × 5 = 20π
Volume of red vessel on its own = π × 3² × 4 = 36π
Volume of blue vessel on its own = π × 4² × 3 = 48π

Volume of water in green vessel = 20π
Volume of water in red vessel = Volume of red vessel - 4/5 × Volume of green vessel = 36π - 16π = 20π
Volume of water in blue vessel = Volume of blue vessel - 3/4 × Volume of red vessel = 48π - 27π = 21π

So the Blue Vessel contains the largest quantity of water.

Author: Peter Grabarchuk
This Puzzle © 2008 Peter Grabarchuk. All Rights Reserved.