It depends on where you're travelling from.
a lot
Nothing, airplanes don't use petrol.
how much petrol will a car use (enginne two liters)
London is a large city, so it will depend on which part of London you are travelling from.
http://www.convertunits.com/drive/from/Bristol,+United+Kingdom/to/London,+United+Kingdom
50 pounds, if you're lucky.
That depends a lot where you start your trip.
The price can vary enormously depending on when you are travelling but a single ticket could be about £115 and a return not much more.
Nothing - thousands of them are issued every day.
It will take just over 4 hours to drive to Plymouth from London and about £45 fuel cost
Question is too vague