For a spring, we know that $F=-kx$, where $k$ is the spring constant.
Therefore, from $F=ma$, we deduce that:
$$a=-\frac{k}{m} x$$
We let $\omega^2=\frac{k}{m}$.
Thus, $a=-\omega^2 x$.
Therefore:
$$-\omega^2 x=-\frac{k}{m} x$$ $$\omega=\sqrt{\frac{k}{m}}$$
From the laws of Simple Harmonic Motion, we deduce that the period $T$ is equal to:
$$T=\frac{2\pi}{\omega}$$
Hence, we derive the following relation:
$$T={2\pi}{\sqrt{\frac{m}{k}}}$$
Therefore, we substitute $m=10$ and $k=250$ to obtain the solution:
$$T={2\pi}{\sqrt{\frac{10}{250}}}={2\pi}{\sqrt{\frac{1}{25}}}={2\pi}{\frac{1}{5}}=\frac{2\pi}{5}$$
$$T \approx 1.257 \text{ s}$$