Question Author
Thank you CrapatCryptics, IJKLM, woofgang and Gromit
for your helpful answers.
The problem is that , being 86 years old and being housebound with severe walking difficulties and not having driven a car for 20 years, I am completely out of touch with petrol prices.
I tried hard to find out petrol prices on the Internet at 7AM this morning without success so I resorted to phoning a couple of local petrol stations.
I asked for the price of a litre of petrol and was told
150p.
Unthinkingly, I then went ahead with the erroneous calculations.
Renewed for your helpful corrections.
this morning without success