> But if you supposed that everyone drove normally until their tank was 1/8 full then refuelled to the top, the average tank would be 7/16 full so if lots of pe

> But if you supposed that everyone drove normally until their tank was 1/8 full then refuelled to the top, the average tank would be 7/16 full so if lots of people refuel all at once that is 9/16 times a lot of fuel tanks. Sorry, extremely minor nit-pick but I think the fractions go the other way. The average tank should be 9/16 full leading to 7/16 of a tank extra per person.