if we take £15837.77 to be the 100% and we increase it by 18.5%, that'll be 100% + 18.5% = 118.5%.
[tex]\begin{array}{ccll} \pounds&\%\\ \cline{1-2} 15837.77 & 100\\ x& 118.5 \end{array} \implies \cfrac{15837.77}{x}=\cfrac{100}{118.5} \implies (15837.77)(118.5)=100x \\\\\\ \cfrac{(15837.77)(118.5)}{100}=x\implies 18767.76\approx x[/tex]
