There are different options that may be used to give sense to the sentence:
Van cinco días que estudio para el examen.
I have studied 5 days for my exam.
Hace cinco días que estudio para el examen.
I have studied for my exam for five days.
Desde hace cinco días que estudio para el examen.
I have studied for my exam for five days.
He contado 5 días que estudio para el examen.
I´ve counted 5 days since I started studying for my exam.
All of them meaning that someone has studied for 5 days for the exam.