b = Bethan's Income
hmmm how much is 32% of "b" anyway?
[tex]\begin{array}{|c|ll} \cline{1-1} \textit{a\% of b}\\ \cline{1-1} \\ \left( \cfrac{a}{100} \right)\cdot b \\\\ \cline{1-1} \end{array}~\hspace{5em}\stackrel{\textit{32\% of b}}{\left( \cfrac{32}{100} \right)b}\implies 0.32b~\hfill \stackrel{\textit{Amrit's Income}}{b~~ + ~~0.32b} \\\\[-0.35em] ~\dotfill[/tex][tex]\stackrel{\textit{\Large Incomes}}{ \stackrel{Bethan}{b}~~ + ~~\stackrel{Amrit}{(b+0.32b)}~~ = ~~\stackrel{combined}{54868}}\implies 2.32b=54868 \\\\\\ b=\cfrac{54868}{2.32}\implies b=23650~\hfill \underset{\textit{Amrit's Income}}{\stackrel{23650~+~0.32(23650)}{\pounds ~31218}}[/tex]