Question

x supra 0,4 =0,005 supra 0,004​

Answer 1

$\frac{x}{0.4} = \frac{0.005}{0.004} \\ \frac{10x}{4} = \frac{5}{4} = > 10x = 5 = > x = \frac{5}{10} = \frac{1}{2} = 0.5$