Air bermasa 20kg bersuhu 20derajat celcius di campur dengan 10 kg air bersuhu 80 derajat celcius jika kalor jenis air 4200 kg derajat celcius hitunglah kalor ya

Diketahui:
m air1 = 20kg
t air1 = 20˚C
m air 2 = 10kg
t air2 = 80˚C
c air = 4200 J/kg˚C
Ditanyakan: tc = ... ?
Jawab:
Qlepas = Qterima
m air2.c air(t air2-tc) = m air1.c air(tc-t air1)
10kg.4200(80-tc) = 20kg.4200(tc-20)
42000(80-tc) = 84000(tc-20)
3360000-42000tc = 84000tc-1680000
3360000 + 1680000 = 42000tc+84000tc
5040000 = 126000tc
tc = 5040000 : 126000 = 40˚C