Energy density $($ED$)$ is the amount of energy released when unit mass of a fuel is completely burned, i$.$e in

$kJ/$Kg

$\frac{E{D}_{\text{e}\text{t}\text{h}\text{a}\text{n}\text{e}}}{E{D}_{butane}}=?$

Assume isothermal combustions at $25C.$

$($Ethane: $C_2{H}_6,$ Butane: $C_4{H}_{10})$