Can a student get admission in BTec in reputed engineering collages if he scores good in mhcet but gets compartment in mathematics.

Unfortunately not. You have to clear all subjects to be a university student. By the time re evaluation results will be out you will have only mediocre colleges left with seat

One can't take admission if he / she doesn't clear a subject in hsc You need to pass all subjects In several states the take the aggregate of marks in HsC plus cet