Thank you... I did not write in c because c for h20 is 1... so...
heat to convert steam to h20+heat to cool steam+ heat to warm h20 = 0
-10,000(540)+10,000(1)(T-100)+500,000(1)(T-40) = 0
-5,400,000 + 10,000T -1,000,000 +500,000T-20,000,000 = 0
26,400,000 =510,000T
T=51.8 C
but which third...