If resulting temperature of the mixture is T∘C then Heat gained by 50g water at 10∘C, H‌gain ‌=mc∆T=50c(T−10) Heat lost by 50g of water at 100∘C H‌loss ‌=mc∆T=50c(100−T) According to principle of calorimetry, Heat gain = Heat loss ⇒‌‌H‌gain ‌=H‌loss ‌ ⇒‌‌50c(T−10)=50c(100−T) ⇒‌‌2T=110 T=55∘C