does teacher somehow manage to pass a student if he get 1 or 2 marks less in ahesc 12th

Moi pcmb r students and bio khon porha nasilo only pcm porhisilo kintu maths exam khon olop beya hoise. 35/40(exam hall t mind ekebare blank hoi goisil eko likhibo pora nai). bio t kiba ke 18-19 korisilo. Kiba pass korar chances ase neki(except grace mark). Mane bio t pass korile 21+30 = 51 something palu hoi. Please someone reply