conversations.from: human
conversations.value: Can you give me some step-by-step instructions for this math problem: James makes potatoes for a group.  Each person eats 1.5 pounds of potatoes.  He makes potatoes for 40 people.  A 20-pound bag of potatoes costs $5.  How much does it cost?
conversations.from: assistant
conversations.value: He needs 1.5*40=60 pounds of potatoes
  So he needs to buy 60/20=3 bags of potatoes
  So it cost 3*5=$15