Three exams

Three exams
 

There are IB, GCE, and O-level.

1. They are public exams, so can I say this?:

-There are students who took three public exams respecitively.

I am not sure, mainly because three exams sounds like three subjects, rather than three systems.

2. Do I need THE for IB, GCE, O-level etc.?

If your audience understands that you're talking about IB, GCE and GCE O-level exams, there is nothing wrong with the sentence (except as corrected above).
If you want to be more clear, state the names of the exams and omit the adverb 'respectively', unless you are trying to convey order.

You do not need to use a definite article.

Thank you, but for

--There are students who took three public exams(,) respectively.

is it ambiguous?

1. A took IB, B took GCE, C took O-level.
2. A, B, and C took IB, GEC, and O-level. (=each having taken part in 3 systems.)

Yes, the sentence is ambiguous.

More clear:
There are students who took all three public exams, each having taken part in three systems.

THank you~