10 g of water at 70°C is mixed with 5 g of water at 30°C. Find the temperature of the mixture in equilibrium.

Let t° C be the temperature of the mixture. From energy conservation,Heat given by 10 g of water = Heat taken by 5 g of water or m1Cwater Δt1=m2Cwater Δt2∴(10)(70−t)=5(t−30)∴t=36.67∘C