Firsly, we can write the numbers in scientific form:
[tex]\begin{gathered} 0.008=8\times10^{-3} \\ 51.3=5.13\times10^1 \end{gathered}[/tex]
Notice that 0.008 has no tailing zeros, so the only significant figure is "8". 51,6 has 3 significant numbers.
In a division, the result will have the same number of significant figures as the one with less significant figure.
Since the one with less is 0.008, that has only one, the result also only has one significant figure:
[tex]\frac{0.008}{51.3}=\frac{8\times10^{-3}}{5.13\times10^1}=\frac{8}{5.13}\times10^{-4}=1.559\ldots\times10^{-4}\approx2\times10^{-4}[/tex]
