1. The problem statement, all variables and given/known data A car making a 100-km journey travels 40 km/h for the first 50 km. How fast must it go during the second 50 km to average 50 km/h? 2. Relevant equations 3. The attempt at a solution I calculated the time to travel the first 50km at 40km/h, to take 1.25 hours. So it take 1.25 hours to drive 50km at 40km/h. So I need to find how fast it must go during the second 50km to average 50km/h. I am confused. Is this a two-part problem?