Answer;
76.3°C
Explanation;
Considering the fact that;
Specific heat capacity of the hot chocolate = 3.751 kJ/kg C°
Specific heat capacity of milk is 3.93 kJ/(kg.C°)
But;
Heat gained by milk = Heat lost by hot chocolate
If the final temperature is x , then
Heat gained by milk
= 0.05 × 3.93 × (x-5)
= 0.1965x - 0.9825
Heat lost by hot chocolate;
= 0.2 × 3.751 × (95-x)
= 71.269 - 0.7502x
Therefore;
0.1965x - 0.9825 = 71.269 - 0.7502x
0.1965 x + 0.7502x = 71.269 + 0.9825
0.9467 x = 72.2515
x = 76.319 °C
Approximately, the new temperature is 76.3°C