Below, you will find information pertaining to two fictitious oil companies:

$\backslash$table$[[,$Profit Margin,Asset Turnover,Equity Multipli$],[$a$)$ Fill$-$Er$-$Up Petroleum,$4\mathrm{.}2\%,1\mathrm{.}10,5\mathrm{.}6],[$b$)$ Exxoff Corporation,$7\mathrm{.}0\%,1\mathrm{.}30,1\mathrm{.}9]]$

Calculate the return on equity $($ROE$)$ for each company.