In an insulated container, .50 kg of steam, initially at 140 C, is mixed with 2.0 kg of ice, initially at -20 C. What is the final temperature inside the container if heat exchanges within the container are ignored?

Answer is 60 degrees C. I did it myself and i got 63.2 degrees C, but another one of the answer choices is 64 degrees C. Please help with the work. Thank you