If 5 kg of coal can generate 9 kWh of electricity, how many kg of coal is needed to generate 1 kWh of electricity?
如果5千克煤可发电9度，那么发一度电需要多少千克煤．
<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<result>5/9 = around 0.555556</result>