Density = mass/volume.
You are given the density and asked to find the mass. So, you need to find the volume. According to Archimedes Principle, the volume displaced by an object is equal to the volume of that object. So, in this problem the volume of the lead is the same as the volume of water that it displaced. That would be
95.6 ml - 73.2 ml = 22.4 ml.
Density = mass/volume
11.3 g/ml = mass/22.4 ml
mass = 11.3 g/ml x 22.4 ml = 253 g (to 3 significant figures)
