The first question: My sister came back to pick up my sister, which means that my sister and my sister * * * did the whole journey twice, 800*2= 1600 meters, and the speed sum was 150+50=200 meters, 1600/200=8 minutes, that is.

Question 2: If you divide the fare by the number of people, you can know that the price of a big car is cheaper than that of a small car, so try to rent a big car, rent four big cars and a bus, and ***950 is the cheapest.