Explaining what a neural network is learning
That's a popular question, since many use cases require to understand what's going on in the model.

I suggest to do just some simulation with the resulting NN. Like in your example you could have a test-dataset and den modify the 'studying_hours' by +5%, +10%, +15%, ... and then plot the result over this modification factor. This way you can see by an simulation what the NN is thinking of the 'studying_hours' and how it influences the result.