What is the volume of 2400 kg of petrol?

In order to answer this question, you must know the density of petrol.  The reason you need to know this is because the formula that you would need to use to find the volume of petrol is

M = DV  where M is the mass, D is the density and v is the volume.  You have given us the mass and you are asking for the volume so we need to know the density.

One value given for this density is 737.22 kg/m^3  I will use this value.  Using this:

2400 = 737.22*v

v = 3.26 m^3