The unsuccessful student should take a small portion of the root of the Gudmar herb and always keep it inside his study book. The Gudmar herb is also known as Gurmar and its botanical name is Gymnema Sylvestre. This is a medicinal plant and is used in Ayurveda and traditional Indian medicine. It also finds use is certain specific Tantric experiments, including ones such as the one given in this post and in Vashikaran and Mohini Vidya Totke.
Along with this, the student should try to chant the Mantra shown in the image, which is a Doha from the Shree Ramcharitmanas and hence is most potent and powerful and will enhance the potency of the Gurmar and help the student successfully pass his examinations.
Mantra for Unsuccessful Students
I have not prescribed any fixed number of Mantra Chant nor any fixed timings or Puja- Vidhi. Hence, the student should memorize the Mantra and chant it whenever he feels like chanting it.