First, we need to determine the mass in g of the liquid. If the cylinder and liquid weighs 39.671 g, and the cylinder alone weighs 34.670 g, then we can subtract the two to determine the weight of just the liquid.
39.671 - 34.670 = 5.001 g
Next, to determine the density (g/mL), we need to divide the mass by the volume.
5.001 g / 9.24 mL = 0.541233766233766 g/mL
But, we need to remember to use significant figures. 5.001 has 4 sig figs and 9.24 has 3. We use the number with the least sig figs, so 3.
Therefore, the answer is 0.541 g/mL
