The usual case is where, to give an example, Physics has a corequisite of Calculus, which means that you must either have taken Calculus before Physics or be taking it at the same time, because you need to know stuff from Calc in the Physics class. However, naturally, you don't need to take Physics to take Calculus.
The other potential scenario is that this other class you don't name is a lab/tutorial/discussion group etc associated with Psych in which case you would have to take it at the same time unless the lab is optional. Labs can sometimes only be required for people intending to major in the subject or something (I took a bio class as an elective which had a lab for people majoring in Nutrition), and if it's optional you may be able to take them separately (or you may not).
Now, the wording of your question isn't clear. Is Psych the "calculus" while the other course is the "physics"? That seems to be the most likely scenario, but your wording seems to indicate the other way around.
Remember that it often takes just as long to do a search or two on Google to try and find the answer to your question as it takes to type it in a post here, let alone the time waiting for a reply.
If your question is "What mark does it take to get into University X", or "What are the requirements to get into University X", it's on their website and/or
electronicinfo.ca (for Ontario schools). Particularly for Ontario schools, those ranges are a pretty good picture of what kind of mark will get you into the program, and if you're more than a couple percent higher it's practically guaranteed unless it requires a supplementary form.
