Calculate Bulk Modulus: Solve Rock Density Problem

[Irishwolf]

Homework Statement

A rock at the surface has a density of 2600kg(m^(-3)
90000m down its density is 3100kg(m^(-3)
Change in pressure at the depth is due to hydrostatic pressure.
Whats the bulk modulus of the rock?

Homework Equations

Δp=p + ƿgh

Δp=-B(ΔV/V)

The Attempt at a Solution

Hydrostatic pressure:
p(90000)= 1 x 10^(5) Pa + (3100kg(m^(-3))(9.81m/s^(2))(90000m)
Δp= 2.74 x 10^(9) Pa

Δp= - B(ΔV/V)

So, (ΔV/V) => ΔV=m/ƿcompressed
And V=m/ƿintital

So the 2 m cancel and the expression for the bulk modulus is
-B=Δp(ƿcompressed/ƿinitial)
B= 3.3 x 10^(9)

I think I may have made a slight misktake please help?

 

[bm0p700f]

B has the right order of magnitude so I think you are fine.

 

[Irishwolf]

B has the right order of magnitude so I think you are fine.

Actually i made a mistake with the Vfinal expression.
My new answer is B= 5.3 x 10^(8)