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