For i40, 1 litre of diesel can travel between 12.5km to 14km
So base on current CDG diesel price of $0.85 per litre
Per km should be between 6 to 7 cents
But of course let the person pumping earn a bit lah 
He need to dirty his hands and take time to pump 
12 to 14km....for 1st years new cab, thereafter, may become
10km/hr. Not only paying the person to pump, also hv to pay for him
to pay at the counter, sometime Q damn long, then counters alway hv
those bak bak pui pui aunties, see liao..more tired.