conversations.from: human
conversations.value: Jason is mixing a batch of black paint. He needs to add 2 grams of charcoal for every 30 ml of water. If he adds 900 ml of water, how much charcoal does he add?
  Find the solution.
conversations.from: assistant
conversations.value: First find how many ml of water Jason needs for 1 gram of charcoal: 30 ml / 2 grams = 15 ml/g
  Then divide the amount of water Jason uses by the amount of water per gram of charcoal to find how much charcoal he uses: 900 ml / 15 ml/g = 60 g