A student drops an ice cube into an insulated flask full of water and waits for the ice cube to completely melt. The ice cube initially has a mass of $105$ g and a temperature of $0\backslash$deg C$.$ The water $($before the ice cube is added$)$ has a mass of $2\mathrm{.}00$ kg and an initial temperature of $85\backslash$deg C$.$ What is the final temperature $($in $\backslash$deg C$)$ of the mixture? $($Assume no energy is lost to the walls of the flask, or to the environment.$)$