Hello aspirant
You have not described your question in detail like whether you are talking about state board or cbse board class 12 examination moreover you have not described about which exam you are talking about it is hard to assist you with proper details. Reframe your question so that i can give you proper details. As most of state board and cbse have same passing criteria i am answering on basis of that.

Cbse passing criteria for class 12 candidate is 33%.
You have to get at least 33% marks in particular subjects to get pass in that subject . overall 33% percentage marks is also necessary to get a pass certificate.

As you have got 25 marks in your 12 you will have to give compartment examination conducted by cbse or your state board .After getting at least 33% marks you will get a pass certificate.

Cbse had started registration for compartment examination for this year.

As most of exam in india ask for 50% aggregate marks to be eligible for examinations try getting good marks.
Many institute set bar of 60% or more in mathematics to be eligible for thier exam so prepare according to that and give your best shot.

Hope this will help you

You can get more information from here

Thank you