{
  "hints": [
    "Average speed = Total distance / Total time. Do NOT average the two speeds.",
    "Time for first part: 40/80 = 0.5 h. Time for second part: 45/60 = 0.75 h.",
    "Total distance = 85 km. Total time = 1.25 h. 85 / 1.25 = 68 km/h."
  ]
}