A cubical block of wood 10 cm on a side floats at the interface between oil and water with its lower surface horizontal and 4 cm below the interface. The density of oil is 0.6 gm/cc The mass of block is

Volume of block = 10 × 10 × 10 = 1000 cm3Volume of block in water = 10 × 10 × 4 = 400 cm3 Volume of block in oil = 10 × 10 × 6 = 600cm3  Weight of block = Weight of oil displaced + Weight of water displaced  mg = (600 × 0.6)g + (400 × 1)        m = 360 + 400 = 760g