After the price adjustment, it is 0.47+7.55=8.02 yuan/liter.

(2) Mr. Zhang waited in line for 72 minutes, followed by a * * * with 2*72/3=48 cars, each car needs 3 minutes, and a * * * needs 48*3= 144 minutes, leaving 48 minutes.

(If there is no car to continue to come, you need to open the tanker 144÷48=3, that is, add two).

The number of vehicles added in 48 minutes is 2*48/3=32, which means that 32+48=80 vehicles need to be refueled before 24: 00.

It takes 240 minutes for 80 cars, and a tanker can work for 48 minutes.

Then a * * * needs 240÷48=5 units, that is, 4 new units are built on the original basis, which can meet the price of all cars and refuel.