Problem

5 g of water at

30^\circ\text{C}

and 5 g of ice at

-20^\circ\text{C}

are mixed together in a calorimeter. Find the final temperature of mixture. Water equivalent of calorimeter is negligible, specific heat of ice =

0.5 \text{ cal/g}\cdot^\circ\text{C}

and latent heat of ice =

80 \text{ cal/g}