If i had strobg chemistry and other subjects are average then is there any percentage for every subject to be scored minimum to qualify ??

There is no minimum cutoff for subjects individually. You can qualify JEE MAIN even though you don't score well in one subject. But you shouldn't think like this. Your should aim to score good marks in all subjects. If you can score good in Chemistry then you can do the same in Maths and physics too. It is just up to you, how you take this.. as a weakness of yours or as a challenge.
Hope you've got your answer. Work hard in Maths and physics too. All the best!!!

Hello buddy, thanks for connecting with us.   There is no such individual cutoff. But your rank will definitely affected. If you  have same score with another student than the student who got higher marks in mathematics got good rank than you and after that physics and than chemistry. So,  to get good rank you should also score good in mathematics also. But now very few days left. You cant do anything . So I advice you don't do any guess estimate in exam. Only attempt those questions that you know.

Best of luck for exam buddy.

AS JEE MAIN 2018 Application form is about to release on 1st December, 2017 and candidates will be able to register themselves for the exam till 1st Jan, 2018. S it becomes important for the student to know and understand the eligibility criteria for the JEE MAIN exam.

The candidates are majorly concerned with Age Limit, Education Qualification, Number of Attempts and one must ensure complete eligibility before appkying for the exam as there are only 3 attempts for the JEE Main exam. The eligibility criteria as per CBSE is as follows-

Age Limit- The age limit to appear in JEE Main 2018-

The candidates should have been born on or after October 1, 1993.

There is age relaxation for SC, ST, PWD candidates of 5 years is applicable.

2. Year of Passing the Qualifying Examination –

The candidates should have appeared for Qualifying Examination in 2016 or 2017 or appearing for the final exams in 2018, but they need to submit the certificates before the due date.

If a candidate did not pass the Qualifying Examination in the year 2015 but passed in 2016 is not eligible.

In IIT JEE exam their are no such subject percentages their are students who actually score well due to their chemistry score.

Dear Bhavesh,

There is as such no sectional cut off in JEE Main but to score good marks you should try to score good marks in each subject.

You can check the cut off of JEE Main from the given below link

https://engineering.careers360.com/articles/jee-main-cutoff

Good Luck!!