conversations.from: human
conversations.value: James buys a weight vest for $250.  He then buys 200 pounds of weight plates for $1.2 per pound.  A 200-pound weight vest would cost $700 but there is a $100 discount.  How much does he save with his vest?
  Give me a detailed solution.
conversations.from: assistant
conversations.value: The weight plates cost 200*1.2=$240
  So his vest cost 250+240=$490
  He could get the other vest for 700-100=$600
  So he saved 600-490=$110