Can we take two board exam same year?

It is neither legal or illegal, it is voidable. Voidable means that which is not absolutely void, but may be avoided.

Which is better Bihar board or CBSE?

CBSE, obviously, provides students with an easier level of examinations comparatively, sticking strictly to the NCERT textbooks. On the other hand, Bihar Board provides you with a better percentile due to lesser students, but the central board, a better percentage. Both of these have their respective advantages.

Can I do matriculation twice?

No it is not illegal . But yes you cannot use both certificate at same time. No there is no law which prohibits you front doing so. You can use only one marksheet for getting admission.

Can I repeat class 12th after passing 12th CBSE board with 59\%?

Re: Can I repeat class 12th after passing 12th CBSE board with 59\%? Yes you can. For that you have to talk to the administrative officers in your school first. They will ask you to send a letter to the CBSE board and thus you can give the exam as an external.

Is it legal to give 12th Boards legally?

Yes you can give 12th boards legally as before giving improvement you have to sign on paper that you will not pursue for higher studies but you should not have compartment in any subject. Same thing happened to me as i got 58.8\%in boards but after improvement i got 75\%.

Can I repeat 12th Board if my percentage is low?

Dear friend, you if you have got low percentage in your class 12th board due to one or two subjects then you have an option to recover them by giving improvement exams. You still can repeat 12th board if you want to if there is not more than 2 or 3 years gap between 10 and 10+2 you are repeating.

Should I give 10th or 12th Board exam first?

If there is a long gap i.e., more than 3 or 4 years then may be you have to first give 10th board exam and then later 12th board exam. Giving your 10th board exam has an advantage also.