tnx i think it is a kind of university that you learn lessons at home by watching them on TV or other equipments and you send your work or assignments to your teacher for example weekly.
The Open University isn't a specific location, doesn't have any buildings constituting a campus. 'in' is used when expressing the situation of something that is enclosed or surrounded by something else Since Open University is a TV and correspondence course, what is a student "enclosed or surrounded by"? 'with' is used to express being a member of something,