Woody's logic game-how to change tires

Question: a long-distance transportation driver is about to depart. the car he uses for transportation is a tricycle and the tire's life is 20 thousand miles. Now he wants to carry out long-distance transportation of 50 thousand miles, how can we complete the transportation task with 8 tires?

First, the tires are numbered from 1 to 8, and then the result is as follows:

1. Use tires 1, 2, and 3 to run 10 thousand miles. At this time, 10 thousand miles left for each tire 1, 2, and 3;

2. I ran 20 thousand miles with 4, 5, and 6 tires. At this time, I ran a total of 30 thousand miles;

3. Replace the rear two with tires 7 and 8, replace the front wheel with tires 1, run 10 thousand miles, and replace tires 1 with tires 2 or 3, and then run 10 thousand miles, to the end.

Woody's logic game-how to change tires