conversations.from: human
conversations.value: Steve decides to start eating more tomatoes and decides to grows his own cherry tomatoes.  He eats twice as much as his girlfriend.  He eats 6 per day.  If a vine can produce 3 tomatoes per week how many vines does he need?
  Work out the solution step by step.
conversations.from: assistant
conversations.value: His girlfriend eats 6/2=3 tomatoes per day
  So together they eat 6+3=9 tomatoes a day
  That means they eat 9*7=63 tomatoes a day
  So he needs 63/3=21 tomato vines