It depends, if you write an essay, three quotes per paragraph, say you have one related and one prescribed, four body paragraphs, that makes it a minimum of 12 quotes altogether, plus you have to remember a few extra quotes in case it doesn't fit into the question-and this also depends on what rubric you are talking about, but I would say 16 quotes altogether seems to be a good bet (but depends on module, for discovery, you might need more, depending on whether you know how to tweak it to the question)
You should focus your energies generally though not on how many quotes you remembered for each text, but how you use these quotes under exam condition to specifically answer the given question-which is the greater determinant of how many marks you will get.