Explain how one of Gettier's original counter examples attacks the tripartite view of knowledge

The tripartite view of knowledge defines propositional knowledge as justified true belief. Edmund Gettier famously contested this definition by providing a series of counter examples which show that there are instances of justified true belief that we would hesitate to call knowledge. One of which is the case of Smith and Jones, where Smith and Jones are both waiting to be interviewed for the same job. Smith overhears one of the interviewers telling her colleague that they are going to give the job to Jones. Shortly after this, Smith observes Jones counting out 10 coins from his pocket. From this, Smith deduces, and believes, the proposition that the man with 10 coins in his pocket will get the job. However, it turns out that it is Smith who gets the job and, unbeknownst to Smith, he also has 10 coins in his pocket. This raises the question of whether Smith can be said to know that the person with 10 coins in his pocket will get the job. Here, Smith has a justified true belief: justified in that his evidence on which this belief is based comes in part from overhearing the interviewer herself asserting that Jones was going to get the job, and from observing himself that Jones had 10 coins in his pocket; true in that it turns out that Smith, the person who gets the job, also has 10 coins in his pocket; and a belief, as Smith comes to believe this propostion upon deducing it. However, despite having this justified true belief, it cannot be said that this is an instance of knowledge. This is because it is merely a coincidence that Smith's justified belief turns out to be true, as part of the evidence on which his belief is deduced - namely hearing that Jones will get the job from the interviewer - turns out to be contrary to the outcome, and Smith is unaware that he also has 10 coins in his pocket. Thus, Smith's justified belief that the man with 10 coins in his pocket will get the job is only true by good luck. Therefore, the tripartite conditions of justification, truth and belief are not jointly sufficient for knowledge, as there are cases in which these conditions are fulfilled yet do not count as knowledge.