A mug contains 0.5 kg of coffee with specific stored energy (e) of 104.5 kJ/kg. If 0.1

Question:

A mug contains 0.5 kg of coffee with specific stored energy (e) of 104.5 kJ/kg. If 0.1 kg of milk with specific stored energy (e) of 20.8 kJ/kg is mixed with the coffee, determine
(a) The initial stored energy (Ei) of the system.
(b) The final stored energy (Ef) of the system, and
(c) The final specific energy (ef) of the system.