The question is in the photo below . Please answer these question

Dear student,
$$\begin{gathered} Given, \\ Density of zinc=4200 kg/m^3 =4.2\times {10}^{3}kg/m^3 \\ Volume=28c{m}^3=2.8\times {10}^{-5}{m}^3 \\ now, \\ Density=\frac{Mass}{Volume} \\ \Rightarrow mass=Density\times volume=4.2\times {10}^3\times 2.8\times {10}^{-5}=.1176 kg or 117.6 g \end{gathered}$$
So, to balance the weight, the known weight must be placed on the other pan  is 117.6 g

Regards,