posted by Walter .
John and Al are in a 15 km race. John averages 4.4 m/s during the first half of the race and then runs at a speed of 4.2 m/s until the last 200m, which he covers at 4.5 m/s. At what average speed must Al run to beat John?
You are doing yourself a disservice by mislabeling your problems, then having teacher go in to answer it and the subject matter is irrelevant to their expertise.