1, they met 200 meters away from the midpoint, indicating that Xiao Pang has many rows of 200*2=400 meters.

Xiao Pang does 250-200 lines per minute = 50 meters.

It takes =400/50=8 minutes to row for 400 meters.

That is to say, they walked the road in 8 minutes, and the length =8*(200+250)=3600 meters.

2. If it is changed to 10 minutes, meet at a distance of 200 meters from the midpoint.

Then directly calculate the highway length = 10 * (200+250) = 4500m.

But it can't meet the contradiction of "meeting at 200 meters from the midpoint".