Preparing for the Joint Entrance Examination (JEE Main) can positively impact CBSE Class 12 Board Exam scores, especially in Physics, Chemistry, and Mathematics, given the overlap in the syllabus. However, a singular focus on JEE may neglect other subjects, potentially affecting overall CBSE performance. Factors like individual learning styles, exam strategies, and time management play crucial roles, making success in both exams contingent on a balanced approach.