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**1. Homework Statement**

An insulated container is filled with 250g of water at 90degrees Celsius. Which of the following, when added to the hot water, will result in the lowest final temperature of the mixture?

A. 10g of water at 0 degrees C

B. 125g of water at 75 degrees C

C. 15g of water at 0 degrees C

D. 5g of ice at 0 degrees C

E. 250g of water at 80 degrees C

**2. Homework Equations**

I used (CM[dT]) + (CM[dT]) = 0

where the first part is the container's heat and the second is the supposed amount of added substance at a certain temperature.

**3. The Attempt at a Solution**

I began plugging in numbers, starting from

A: the final temperature was 86.5

B. the final temperature was 85

C. The final temperature was 84.9

D. The final temperature was 88.23

E. The final temperature was 85.

It seems that C would be the answers, but it's just too close to B and E. Also, I think that my equation is wrong because ice has latent heat... so logically, I think that D would be the right one, because it takes heat to first melt the 5g of ice. But could anyone help me with how I should set up the equation due to the latent heat of ice?