CBSE

If you fail in 2 subjects out of 6 subjects in Class 12th CBSE you will not be eligible to clear the Class 12th Board exam. In CBSE a student needs to pass in at least 5 subjects including one language subject to be considered as passed in the Class 12th Board exam. However, if you have failed in 1 or 2 subjects, you may be eligible to appear for the CBSE Class 12th compartment exam. The compartment exam is a second chance given to students who have failed in one or two subjects in the main exam to clear their papers and obtain their passing Certificate. The compartment exam is usually held in July/August, and students have to fill a separate compartment exam application form and pay the exam fee. If you clear the compartment exam, you will receive a passing Certificate. And you will be eligible for admission to higher education courses.

There is no such criteria ( minimum JEE marks) for admission in to SASTRA university . SASTRA university has a separate procedure through stream 1 and stream 2 .
Stream 1 .
70 percent seats of every branch are filled through stream 1 based on 12 th percentage ( 75 percent after normalisation ) + JEE mains score ( 25 percent )
For example
12 th percentage - 88 (CBSE) and JEE mains score is 80 .
Normalised percentage of board would be as follows
88 * 100/98.6 = 89.25
( Assuming percentage of topper is 98.6 )
Now 89.25 * 0.75 + 80 * 0.25 =86.94
This is your final score . AIR (SASTRA) is prepared based on this final score . There is a chance AIR up to 4000 .
If someone is a topper of board exam and his JEE mains score is 40 then final score would be 85 and AIR (SASTRA) would be above 5000 . It proves thatthere is no chance for JEE mains score below 40 in stream 1 .
Stream 2 .
30 percent seats of every branch are filled through stream 2 based on 12 th percentage .
There is very less chance for percentage below 95 in stream 2 .