A solid wooden block with a uniform cross section is floating in water (density _ w ) with a height h₁ below water. Now a flat slab of stone is placed over the wooden block but the block still floats with a height h₂ below water. Afterwards the stone is removed from the top and pasted at the bottom of the wooden block. The wooden block now floats with a height h₃ under water. Therefore, the density of the stone is