There is only one question I am slightly stuck on. Here it is:

A concrete lintel of 2.6 x 0.15 x 0.10m and density 2215 kg/m3, is reinforced by two 15mm diameter steel bars. Assuming the density for mild steel to be 8000kg/m3, calculate the mass of concrete in the lintel.

Someone please help! It would be much appreciated!