The minimum marks vary every year. The last year it was 24,however the cut off marks changes every year but you need not worry as every year, the cutoff marks for different categories has been decreasing continuously. Best of luck for your future and I hope that you qualify in the exam. 

hello srinivas,

as per previous year analysis, minimum cutoff marks required to clear jee mains for st students is "24".

it may varies year to year depending up on the students attempted the exam and complexity of the paper. 

cutoff will be released by NTA once after the announcement of results. 

we can expect, the marks should be in range of 24-40 to clear jee mains for st students and get admission in the prescribed colleges mentioned to that particular marks. 

thank you