For an initial screening of an entrance exam, a candidate is given fifty problems to solve. If the probability that the candidate can solve any problem is \( \frac{4}{5} \), then the probability that he is unable to solve less than two problems is
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Probability Tip:Pay close attention to phrasing: "unable to solve" flips the definitions of $p$ and $q$ from how they are initially presented in the text.
"Less than two" strictly means 0 and 1. It does not include 2.