Each and every subject of 11 and 12 will be considered for calculation of jee main score. Get more than 75%, then only you will be eligible for nits

The eligibility criteria for the jee is that the aggregate of the class(11&12) including all subjects should be greater than 75%. Not only the PCM you have to focus on the remaining subjects too to get 75% aggregate and to eligible for jee. So plan according to that manage both board and jee preparations and don't neglect board examinations it's percentage also plays a key role in jee examinations.
All the best prepare well for your exams.

It's overall %age . You should score 75% to eligible for Jee main. The rank will be decided on score that you will get in your jee main exams. There is no weightage for Board marks. Board marks is just eligibility criteria.

75 in gujrat board and 70 to 80 in gujset

Overall score of 75% is considered you need to get atleast 75% to be eligible for the jee exam