Is there a way to solve this problem using combinations? I've been getting to the given correct answer using trial and error but I want to know if there's a way using something related to combinations or permutations? Here's the problem:
A teacher is providing her students with 4 special lessons. (a) Each lesson has exactly 3 participants, (b) Any two students must attend at least one special lesson together. According to these two conditions, what is the maximum number of students who can join these special lessons?