E15 and E85 are biofuel mixtures containing ethanol and petrol. The table below shows information about these dual-component fuels:

\begin{array}{|c|c|c|} \hline \textbf{Fuel} & \textbf{Percentage (%) by mass of ethanol} & \textbf{Percentage (%) by mass of petrol} \\ \hline \text{E15} & 15 & 85 \\ \hline \text{E85} & 85 & 15 \\ \hline \end{array}