conversations.from: human
conversations.value: Calvin buys a pack of chips, for $0.50, from the vending machine at lunch, 5 days a week. After 4 weeks, how much money has Calvin spent on chips?
  Work out the solution step by step.
conversations.from: assistant
conversations.value: The chips cost $0.50 a bag and he buys them 5 days a week so that's .50*5 = $2.50 a week
  If he spends $2.50 on chips a week then over 4 weeks he will spend 2.50*4 = $10.00 on chips