As anywhere else, it depends where you shop. I was in Calais and Dunkerque three days ago (Oct 21 2012) and unleaded 95 ranged from 1.51 to 1.58 euro/litre, while diesel was 1.29 to 1.51. Checking an appropriate website, I see that individual stations can offer prices both above and below those. You can check on http://www.zagaz.com/prix-carburant.php?id_div=35087, noting that 'gas' means diesel.
1 litre of petrol
Petrol cost Rs 7.60 per litre in India.
From Cardiff to Glasgow is some 400 miles and would cost about £75 in petrol.
50 dollars
it's about $2.00
£1.20 ish
It depends on the cost of said petrol and the efficiency of the vehicle in "miles per unit of petrol". You didn't supply enough information.
Nothing, airplanes don't use petrol.
about 35 cents
That is totally dependent on the price for the petrol and and the miles per gallon rating on the vehicle.
a million bucks kid
in ireland its approx €1.59 to €1.69