You pour 250 gram of tea into a Styrofoam cup, initially at 80oC and stir in a little sugar using a 100 gram aluminum 20oC spoon and leave the spoon in the cup. Suppose the specific heat of tea is 4180 J/kg⋅oC and the specific heat of aluminum is 900 J/kg⋅oC.
Obtain the highest possible temperature of the spoon when you finally take it out of the cup?