5.45 3/2 35 24/5 (process omitted)

leave out

7.

(1) 30:1= 60/2 = 90/3 =120/4 = 30 answer: distance is proportional to time, because distance/time = speed (certain), then distance is proportional to time.

(2) Answer: It takes 5 hours for this car to travel 150km, and it can travel in 6 hours 180km.

8.

(1) 5/0.5 =101=1015/1.5 =10 The driving distance must be.

(2) The distance from Chengdu to Dujiangyan is 50km, and the automobile fuel consumption is 5L.

(3) The answer is 80/10 = 8 (l) 8l > 6L answered that he needed to refuel.

We haven't done the next class yet, so ...