Xiaojun's home is 800 meters away from his grandmother's. One day, he brought a dog from home to his grandmother's house. As soon as he set out, the dog ran to her house and came back as soon as he go

Xiaojun's home is 800 meters away from his grandmother's. One day, he brought a dog from home to his grandmother's house. As soon as he set out, the dog ran to her house and came back as soon as he got there. Xiaojun's home is 800 meters from his grandmother's house, and his speed is 40 meters per minute. The time to his grandmother's house is 800÷40=20 minutes, and then the dog keeps running for 20 minutes, that is, 20×200 (the speed of the dog) =4000 meters.

The dog ran 4000 meters (easy to run! ! )