Two wires are made of the same material and have the same volume....

\begin{aligned} & \mathrm{A}_1 \ell_1=\mathrm{A}_2 \ell_2 \Rightarrow \ell_2=\frac{\mathrm{A}_1 \ell_1}{\mathrm{~A}_2}=\frac{\mathrm{A} \times \ell_1}{3 \mathrm{~A}}=\frac{\ell_1}{3} \Rightarrow \frac{\ell_1}{\ell_2}=3 \\ & \Delta \mathrm{x}_1=\frac{\mathrm{F}_1}{\mathrm{~A} \gamma} \times \ell_1 \\ & \Delta \mathrm{x}_2=\frac{\mathrm{F}_2}{3 \mathrm{~A} \gamma} \ell_2 \\ & \text{ Here } \Delta \mathrm{x}_1=\Delta \mathrm{x}_2 \\ & \frac{\mathrm{F}_2}{3 \mathrm{~A} \gamma} \ell_2=\frac{\mathrm{F}_1}{\mathrm{~A} \gamma} \ell_1 \\ & \left.\mathrm{~F}_2=3 \mathrm{~F}_1 \times \frac{\ell_1}{\ell_2}=3 \mathrm{~F}_1 \times 3=\mathrm{i}\right) \end{aligned}