Can one select 102 17-element subsets of a 102-element set so that the intersection of any two of the subsets has at most 3 elements?
I'm not sure how to approach this problem. I think it might be useful to try to find a generalization of the result so one can work with smaller numbers and try to find useful lemmas/properties. In particular, $17$ is prime, so one could replace that with $p$. Then $p(p+1)/3 = 102.$ So it might be reasonable to guess that one can always select $p(p+1)/3$ $p$-element subsets of a $p(p+1)/3$-element set so that the intersection of any two of the subsets has at most $3$ elements. Also, $17\cong 2\mod 3, 17\cong 2\mod 5.$ For $p=2,3$ the problem is straightforward. For $p=5,$ we need to find $10$ $5$-element subsets of a 10-element set so the intersection of any two has at most $3$ elements. I'm not sure how to find the subsets in this case.
It might be useful to consider something related to modular arithmetic modulo the prime p.