what is the density of the wood, and the oil?

Question

A block of wood floats in fresh water with two-thirds of its volume V submerged and in oil with 0.90V submerged. please explain how to find the density of the wood and oil, thanks!

Answer 1

Let density of wood=dw; density of oil=do; desity of water=1g/cc
2/3*V=weight of water displaced=weight of wood=V*dw; hence
dw=2/3 g/cc.
0.9*V*do=weight of wood=V*dw=V*2/3; hence do=0.74 g/cc

Answer 2

mesab gave that i think.