The temperature of equal masses of three different liquids A, B and C are 12°C, 19°C and 28°C, respectively. The temperature when A and B are mixed is 16°C and that when B and C are mixed is 23°C. The temperature when A and C are mixed is

Heat gain = Heat lost⇒CA(16−12)=CB(19−16)⇒CACB=34and CB(23−19)=CC(28−23)⇒CBCC=54⇒ CACC=1516               …(i)If θ is the temperature when A and C are mixed, thenCA(θ−12)=CC(28−θ)⇒CACC=28−θθ−12            …(ii)On solving Eqs. (i) and (ii), θ=20.2∘C