Hello aspirant,
I am here for helping you...

by considering your doubt I am clarifying you that for having a good chance in polytechnic exam you will have to score at least 55% of your total marks.
If you scored this much was there any chances will be in your favour.
And apart from this there are so many possibilities to have chance below these marks.
I hope it will be beneficial for you....
For more queries you can upvote my answer and can ask in the comment section below...
Best of luck...