The passing marks out of 30 is not a universal standard and can vary depending on the exam or educational institution. However, based on the available search results, we can provide the following information:

• In a given table of marks obtained by students, if the passing mark is 30, the number of failure students from section A and B together who score less than 30 marks is 35.
• In an example problem where a candidate scores 25% marks in an exam and failed by 30 marks, the passing marks are 80.
• A search result mentions passing marks for physics exam out of 60 is 21, but it is not clear which educational institution or exam this refers to.
• For CBSE exams in India, the passing marks can vary depending on the subject and total marks. For example, in 2023, the minimum passing marks in CBSE Class 10 exam is 33% of total marks, which would be 26 marks out of 80.

Therefore, the passing marks out of 30 cannot be determined without additional context.