The final temperature will be
In order to solve this problem you need the specific heat of both copper, which is listed at
So, the key to this problem is the fact that the heat lost by the hot metal when placed in the cooler water is equal to the heat gained by the water. So,
This means that
Let's assume that the final temperature is
Solving this equation for
Notice how extreme the drop in temperature is for the metal and how small the increase in temperature is for the water; this happens because of the bigger specific heat value water has.