1. The problem statement, all variables and given/known data A family travels from hither to yon one afternoon. On this day, the driver spends half the distance traveling at 77 km/hr and the remaining half at 50 km/hr. What is the average speed during the trip? 2. Relevant equations 3. The attempt at a solution I assumed that the trip was 2 hours. If each speed is half the distance of the total trip, then 77 km/hr lasted for .82467 hours, and 50 km/hr lasted 1.27 hours. I then found a weighted average, [77(.82467) + 50(1.27)] / 2 For 63.5 km/hr, which is incorrect. What part of my process is wrong?