Buoyancy problem. Please help!

[TRBMan]

1. The problem statement, all variables and given/known data
A ferry boat is 4.0 m wide and 6.0 m long. When a truck pulls onto it, the boat sinks 4.00 cm in the water. What is the weight of the truck?


2. Relevant equations
\rho=m/v
and others


3. The attempt at a solution
none. My teacher gave my class chapter to read and complete on our own. I have no idea where to begin to start solving this problem.

[Delphi51]

Water must be displaced to get the buoyancy to hold up the truck. The weight of the water displaced will be same as the weight of the truck.

[TRBMan]

do i use the P=m/v equation and solve for m?
i would use the density of water for P, and the volume of the water displaced for v, right? I think i understand.
would the answer be 960 kg?

[Delphi51]

That's it.