200g of water at 90°C is mixed with 100g of water at 30°C. What is…

200g of water at 90°C is mixed with 100g of water at 30°C. What is the final temperature?

Correct Answer: Option C

Explanation

Heat lost = heat gained
200 x c x (90 – (theta))= 100(times) c (times) ((theta – 30))

Dividing through by 100c, we have

2((90 – theta)) = ((theta – 30))

simplifying, we have

(theta) = 70°