Are you suggesting people who do not pass exams are inherently less intelligent? I think in both cases the answer is partly, because in both cases some kind of

Are you suggesting people who do not pass exams are inherently less intelligent? I think in both cases the answer is partly, because in both cases some kind of misfortune prevents them from achieving the desired result, and brain not functioning well is one such misfortune. There are many other ways to become poor, so being poor won't tell you much about intelligence, but most of less intelligent people will be poor.