Check the picture below.
F = sales for Friday
we know that the total of weekend sales for Germany was F + 317 + 405.
we also know that 405 is really 37.19% of that amount, say "x", which is the 100%, so
[tex]\begin{array}{ccll} amount&\%\\ \cline{1-2} 405&37.19\\ x&100 \end{array}\implies \cfrac{405}{x}=\cfrac{37.19}{100}\implies 40500=37.19x \\\\\\ \cfrac{40500}{37.19}=x\implies 1089~\approx ~ x \\\\[-0.35em] ~\dotfill\\\\ \stackrel{friday}{F} + \stackrel{sat/sun}{317} + \stackrel{monday}{405} \approx 1089\implies F +722 \approx 1089\implies \boxed{F\approx 367}[/tex]
