To a sample of water at 23.4C in a constant-pressure calorimeter of negligible heat capacity is added

Question:

To a sample of water at 23.4°C in a constant-pressure calorimeter of negligible heat capacity is added a 12.1-g piece of aluminum whose temperature is 81.7°C. If the final temperature of water is 24.9°C, calculate the mass of the water in the calorimeter.