An open top tank within the lab contains a hot fluid which is gradually cooled whilst the fluid is circulated by a paddle wheel immersed in it. Initially the internal energy of the fluid is 700 kJ and...

The question is in the images, i am having difficulties getting the correct answer, if you could show each stage of the questions . Thanks

Extracted text: An open top tank within the lab contains a hot fluid which is gradually cooled whilst the fluid is circulated by a paddle wheel immersed in it. Initially the internal energy of the fluid is 700 kJ and during the cooling process the fluid loses 400 kJ of heat, and the paddle does 50 kJ of work on the fluid. Describe the thermodynamic operation and properties of this system and the names associated with this type of system. By applying the first law of thermodynamics explain what the final internal energy of the fluid will be.