Hi Ramya,

I am not really sure :\ I don't think there is a time limit once the exam is open to complete it. However I don't think you can save it and come back later to finish either. (If anyone knows different please correct me)

I believe most students download and print a copy of the exam and write the answers on a hard copy then come back and enter them on the online exam. If that helps you any.

Best wishes,
Lisa:)