Opinions are divided on whether studying in a group or individually is better for students. In my opinion, the answer depends on the specific subject that the student is taking.
It is widely believed that some academic subjects need to be studied with others to yield the best results. One of them is foreign languages, particularly speaking skills, which are virtually impossible for students to practice by themselves. As for writing skills, it is a common mistake that what one writes may be clear and easy to follow for the writer themselves, but not necessarily for others, so having someone around to cross-proofread would be useful. Besides, practicing with others helps students stay committed to the learning process. It is widely known that mastering a language can take several years, and minor improvements gained from just one study session could possibly lead to boredom and frustration without a partner to share the experience.
On the other hand, subjects related to science, both natural and social, often require absolute concentration. When one is trying to solve a complex math problem, it would be very distracting if they were surrounded by other people. Furthermore, it could be in their best interest to personally figure out how to solve the problem, as a solution coming from others would seemingly not help develop their reasoning skills. For social science subjects, such as History or Literature, in my home country, Vietnam, students are expected to remember a huge amount of information, ranging from various pieces of data to milestones throughout a certain historical era. Such memorization seems to come more easily when students study alone, such as at home or in a library.
In conclusion, there is a wide range of academic subjects in the school curriculum and there are no one-size-fits-all answers in terms of how to study all of them. For subjects requiring collaboration and interaction, studying in a group would be more effective, but it is likely not the case in scientific fields.