How much gasoline can they make out of a barrel of oil?
That is one interesting question. It is difficult to put a number as such. When you distill crude oil, you dont get only gasoline. There are many other products. Refiners control how much of which “cut” they want by controlling temperature-pressure in various sections of the distillation units. Then the “cuts” are sent further down the refinery in order to get the finished products such as gasoline, diesel, aviation fuel, naphtha, coke etc etc. One can not say – “I want only gasoline out of this barrel of crude”.