First of all I don't know in which class are you.
class 10th maths can be easily passed in 3.5 days . You can literally solve all chapters from NCERT n it's examples in these days . I will prepare my maths in 2 days which are sufficient.
it mainly depends upon how good u r at studies,so if you are weak catch your faculty tell them to teach main chapters main concepts again .
if u r in class 12th the time is less but just focus upon the maIn chapters from which questions every year are common.