I’m not sure if this piece of information is at all useful, but assuming we wanted to know, it’s probably safe to assume that Math II scores are fairly correlated with Physics and Chemistry scores, the number of scorers will be significantly higher than (.19)(.09)(.12)N, where N is the number of test-takers who took all three.
However unless we have data or a good random sampling, I feel like putting a confidence interval on N is already not that easy. Note that there are thousands of test-takers like me, who only took Math II and one science test (in my case, physics) just to satisfy the admission requirements to certain universities.