conversations.from: human
conversations.value: This math problem has got me stumped: A portable computer drive has enough kilobytes of storage space to store 2000 photos. Each photo is 1.5 kilobytes in size. How many 200-kilobyte videos can it store if it already has 400 photos on it?
  Can you show me the way?
conversations.from: assistant
conversations.value: The drive has 1.5 * 2000 = 3000 kilobytes of storage space.
  It already has 1.5 * 400 = 600 kilobytes of storage space taken up.
  Thus, it has 3000 - 600 = 2400 kilobytes of space left.
  The portable drive can store 2400 / 200 = 12 200-kilobyte videos on it with 400 photos.