\(\frac{3}{4} V \times \rho_2 \times g=\frac{1}{2} V \times \rho_1 \times g\) \(\left\{\begin{array}{l}V=\text { Volume of block } \\ \rho_1=\text { density of liquid } 1 \\ \rho_2=\text { density of liquid } 2\end{array}\right.\)
\(\Rightarrow \frac{\rho_2}{\rho_1}=\frac{2}{3}\)