conversations.from: human
conversations.value: Please show me the solution for: A company sold 4000 gallons of milk in jars to Mr. Marcellus' store at the cost of $3.5 per gallon. However, Mr. Marcellus later realized 2/5 of the amount of milk he purchased had passed the expiry date and could not be sold. He returned the sour milk to the company and ordered a refund. Calculate how much he got in refunds.
conversations.from: assistant
conversations.value: If he purchased 4000 gallons, the number of gallons expired is 2/5 * 4000 gallons = 1600 gallons.
  If each gallon costs $3.5, and he returned 1600 gallons for refund, the total amount he got from the refund is $3.5/gallon * 1600 gallons = $5600