conversations.from: human
conversations.value: The cell-phone recharges at the rate of 1 percentage-point of charge per 3 minutes. Now, the phone is at 60% charged. How long will it take to fully charge, in hours?
conversations.from: assistant
conversations.value: 100-60=40 percentage points.
  Then 40*3=120 minutes to fully charge.
  And 120/60=2 hours.