1. The problem statement, all variables and given/known data What would be the final temp if you mixed 1 liter of 20°C water with 4 liters of 40°C water? This question is very straightforward, and is, of course, assuming total conservation of temp. 2. Relevant equations My book mentions q=mc∆t, but using that equation, I get calories as the units. And this equation I barely know how to use. 3. The attempt at a solution My guess is the answer is 38.75 °C, but I figured that by reasoning only, as I have no clue what equation to use. I wondered if it might be a proportions prob, but haven't gotten a logical answer that way. I know the answer has to be over 20°C but under 40°C. I am very very confused, so a clear answer with an good explanation would be the best! Thanks very much!