Examination probability
Source: Brazilian Math Olympiad - University Level - Galois-Noether 2018 #8
November 24, 2019
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Problem Statement
A student will take an exam in which they have to solve three chosen problems by chance of a list of possible problems. It will be approved if it correctly resolves two problems. Considering that the student can solve five of the problems on the list and not know how to solve others, how likely is he to pass the exam?