The water pressure of a sink has a steady flow of 2 cups per 10 minutes for the first 30 minutes. It still flows at 2 cups per 10 minutes for the next 30 minutes after. For the next hour, the water pressure maximizes to 4 cups per 10 minutes and stops. Shawn now has to dump half of the water away. How much water is left? Let's think first. Chain of thought:
For the first 30 minutes, 3 * 2 = 6 cups of water came out. For the next 30 minutes, 3 * 2 = 6 cups of water came out. For the next hour, 6 * 4 = 24 cups of water came out. A total of 6 + 6 + 24 = 36 cups of water came out. Shawn had to dump water which left 36 / 2 = 18 cups of water.
Therefore, the answer is 18.