$\Rightarrow 4 \pi^{2}=\frac{\mathrm{k}}{\mathrm{m}}$
If block of mass $\mathrm{m}=1 \mathrm{kg}$ is attached then, $k=4 \pi^{2}$
Now, identical springs are attached in parallel with mass
$\mathrm{m}=8 \mathrm{kg}$, Hence, $k_{e q}=2 k$
$f^{\prime}=\frac{1}{2 \pi} \sqrt{\frac{\mathrm{k} \times 2}{8}}=\frac{1}{2} \mathrm{Hz}$