Hello Aspirant!

CBSE generally thinks about the welfare of its students. So, although you have made quite a silly mistake by not writing the question numbers of the questions containing 15 and 12 marks respectively, you can stay hopeful. It depends a lot upon the Examiner evaluating your answer script. If he/she wishes to consider your mistake and be merciful, you will get marks in those answers if they are correct.

Best wishes!