Jack leaves his bathtub's faucet dripping at a rate of 40 ml/minute. Water evaporates from the bathtub at a rate of 200 ml/hour. If he leaves the water running for 9 hours, then dumps out 12 liters, how many milliliters of water are left in the bathtub? Let's think first. Chain of thought:
First find how much water fills the bathtub per hour: 40 ml / minute * 60 minutes / hour = 2400 ml / hour. Then subtract the water that evaporates to find the total amount of water added per hour: 2400 ml / hour - 200 ml / hour = 2200 ml / hour. Then multiply that amount by the number of hours to find the total amount of water in the tub: 2200 ml / hour * 9 hours = 19800 ml. Then find the number of milliliters in 12 liters: 12 liters * 1000 ml / liter = 12000 ml. Then subtract the water Jack removes from the total amount of water to find the remaining amount of water: 19800 ml - 12000 ml = 7800 ml.
Therefore, the answer is 7800.