Answer:
36°C
Explanation:
Heat gained by the cold water = heat lost by the warm water
mCΔT = mCΔT
(1000 g) (4.184 J/g/K) (T − 20°C) = (4000 g) (4.184 J/g/K) (40°C − T)
1000 (T − 20°C) = 4000 (40°C − T)
T − 20°C = 4 (40°C − T)
T − 20°C = 160°C − 4T
5T = 180°C
T = 36°C