conversations.from: human
conversations.value: Wendy is five times as old as Colin will be seven years from now. In 25 years, Colin will be a third as old as Wendy is now. How old is Colin now?
  Solve it.
conversations.from: assistant
conversations.value: Let x be Colin's age now.
  (x+7)*5=(x+25)*3
  5*x+35=3*x+75
  2*x=40
  x=20