Can we say some people having duplicate knowledgae of something?

English as a Second Language English Vocabulary, Grammar and Idioms
1

Dear teachers,

My friends, Jan and Susan are both students from different schools.
Jan is studying Biology and Susan is studying Life Science.

Jan have been doing some research on Elephants for some months.
Susan had finished some lessons about Herbivore (e.g. elephants).

Now that Jan and Susan both know something about Elephants,
can I say that Jan and Susan have duplicate knowledgae of elephants?

Sorry that I don’t know other vocabularies to replace the word “duplicate” in my question,
please suggest me some other vocabularies, teachers.

Thank you.

Kitty.

2

That sentence sounds odd, but apart from anything else, it doesn’t follow that they have exactly the same knowledge, which is what use of ‘duplicate’ indicates.

Jan and Susan both have some knowledge of elephants.

If you really wish to indicate that they have exactly the same knowledge, then I suggest you say they have a shared knowledge of elephants.