Calculating Mass of Dry Wood in Buoyancy Problem

[sakebu]

Homework Statement

A pig of mass (1158kg) is placed on a fart made of dry wood. The raft completely submerged in water so that the raft's top surface was just level with the surface of the lake. If the raft's volume was 3.40 m^3, what was the mass of the raft's dry wood? Density of water is 1000 kg/m^3

Homework Equations

m' = (p2 - p1)V
p = density
V = Volume

Buoyant Force
B = pfluid(g)Vobj

Gravity
mg

The Attempt at a Solution

I have no idea where to begin with this. The only density I am given is of water not of the wood.

 

[Delphi51]

Buoyant force = weight of pig and raft