The cars dashboard will either have an arrow next to the gas tank icon which points to the correct side or the gas tank icon's hose will indicate which side the tankis on; works 100% of the time that I have checked.
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The answer above is not true. Sorry - there is no simple way to tell which side it's on, you are going to have to think for yourself.
It's easy to forget or not to notice, especially in a new car or a rental, which side of the pump to pull up to in a gas (petrol) station. In many automobiles, there is a little icon of a gas pump...
What I would do is fill the gas tank all the way up. Note the cost of the fuel and the amount of gallons it took to fill it. Clear your trip meter so that it is on zero. then run the vehicle for a...