Hi,
Good Day. I have read and understand your requirements. You want to develop an online exam system. You also want to create your question/answer list with it. It select questions randomly and start time counter with it. after that time i will not collect answers and submit the result.
I will suggest to make it from scratch. It will be 100% as per your desires. Dont ask for any pre developed solution. The best choice will be PHP and MySQL.
We are ready to work for you. We have a good team of Graphic Design, HTML, PHP, Web Hosting, Website Design. From last 10 years we are working in Web development field. We have a good portfolio for your trust.
We are Flexible with our timings.
Hope to hear you soon.
Thanks