conversations.from: human
conversations.value: Duncan's age eight years ago was two times Adam's age four years ago. If Duncan's age is 60 now, how old will Adam be in 8 years?
conversations.from: assistant
conversations.value: Eight years ago, Duncan was 60-8 = 52 years old, the same as Adam's age four years ago.
  Therefore, four years ago, Adam's age was 52/2 =26 years.
  Currently, Adam is 26+4 = 30 years old.
  In 8 years from now, Adam will be 30+8 = 38 years old.