Suppose you mix 75 g of water at 15 °C with 25 g of water at 75 °C. Predict the final temperature

Answer 1

The 75 g of cold water must heat up 1/3 times as much as the 25 g of hot water cools down.

Of the initial 60 C temperature difference, the cold water heats up 1/4 of the 60 C, or 15 C.

The 75 g therefore heats to 15 + 15 = 30 C, while the 25g of hot water cools to 75 - 45 = 30 C

30 C is the answer