How much force is needed to lift a marble slab under water? Slab volume 0.015 m3

The force of Archimedes and the force of gravity act on a marble slab in water. The forces are directly opposite and to hold the plate you need to apply a force in the direction of the Archimedes force vector.
P = m * g – ρw * g * V, m – slab mass (m = ρ * V, ρm – marble density (ρm = 2700 kg / m ^ 3), V – slab volume (V = 0.015 m ^ 3) ), g is the acceleration of gravity (g = 10 m / s ^ 2), ρ is the density of water (ρw = 1000 kg / m ^ 3).
P = 2700 * 0.015 * 10 – 1000 * 10 * 0.015 = 405 – 150 = 255 N.
Answer: To hold the plate, you need to apply a force of 255 N