{
  "hints": [
    "The fraction shown is corrupted. Use 60 km at 100 km/h and 90 km at 75 km/h.",
    "Time = 60/100 + 90/75 = 0.6 + 1.2 = 1.8 h.",
    "Average speed = 150 / 1.8 = 83.33... which rounds to 83 km/h."
  ]
}