Given that William guesses random answers for the last four questions and that each question has five answer choices.
The probability that he gets an answer correct is 1 / 5.
The probability that he did not get an answer correct is 4 / 5.
The probability that he will not get any of the 4 questions correctly is
[tex]\left( \frac{4}{5} \right)^4= \frac{256}{625} [/tex]
Therefore, the probability that he gets at least one of the 4 questions correctly is
[tex]1-\frac{256}{625}= \frac{369}{625} =0.59=59\%[/tex]
