conversations.from: human
conversations.value: Oscar wants to train for a marathon. He plans to add 2/3 of a mile each week until he reaches a 20-mile run. How many weeks before the marathon should he start training if he has already run 2 miles?
  Can you solve this problem?
conversations.from: assistant
conversations.value: Oscar needs to increase his maximum running time from 20 - 2 = 18 miles.
  Oscar will need a total of 18 / ( 2 / 3 ) = 27 weeks to prepare.