A combination of 0.250 kg of water at 20.0C, 0.400 kg of aluminum at 26.0C, and 0.100

Question:

A combination of 0.250 kg of water at 20.0°C, 0.400 kg of aluminum at 26.0°C, and 0.100 kg of copper at 100°C is mixed in an insulated container and allowed to come to thermal equilibrium. Ignore any energy transfer to or from the container and determine the final temperature of the mixture.