First of all, this question sets a trap, that is, it takes a team an hour to get through the road. What does this mean? This means that it has been told in the title that the road is clear after one hour, and we will come to see the second team again. It takes 2.5 hours for the second team to reach the landslide (from camp 10KM), so when the second team reaches the landslide after 2.5 hours, the first team must clean up the landslide. That is to say, the first team arrives at the landslide at least one hour in advance (from the camp 10KM). As long as the first team guarantees to arrive at the landslide one hour earlier than the second team, and then it takes one hour to get through the landslide, the time for the second team to arrive at the landslide will not be affected, and then the second team will go ahead at a speed of 4KM per hour. This is very easy to calculate. Distance 10KM, and the speed of the second team is 4KM per hour. Then it takes 2.5 hours for the second team to reach the landslide, and it takes at least 1.5 hours (before) for the first team to reach the landslide, so the distance is 10KM, the time taken by the first team is 1.5 hours, and the speed of the first team is 20/3 km/h. Give it to the children!