What is the answer to this buoyancy question? Please explain every step.?

When an object, any object, floats, the buoyancy B = W the weight of the object. Thus, the weight of the ship is W = mg = 20000*9.81 = 19.6 X 10^4 Newtons = B is the buoyancy.

If the object sinks, the buoyancy B = rho g V; where rho is the density of the water (e.g., 1 kg/L for fresh water), g = 9.81 m/sec^2, and V is the volume of the water displaced by the sinking object. If V = Ah, where A is the cross sectional area of the ship, then h is the depth the ship sinks into the water. If h >= H, the height of the ship, then the entire ship is immersed.

When W > B, the ship will sink because there is insufficient buoyancy to keep it afloat. In which case we know that the buoyancy is less than the weight of the ship cited earlier. We can write W > rho g V and solve for V < W/(rho g) to find out how much water the ship can displace and still sink. But without knowing the volume of water displaced by the sunk ship, we cannot get an exact number of the buoyancy.