\textbf{Question 5:} An unknown code consists of 8 characters.\\
Each character can be a letter or a digit. There are therefore 36 usable characters for each position.\\
A code-breaking software tests approximately one hundred million codes per second. In how much time at most can the software discover the code?

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\begin{tabular}{l} a. approximately 0.3 \\ seconds \\ \end{tabular} & b. approximately 8 hours & c. approximately 3 hours & \begin{tabular}{l} d. approximately 470 \\ hours \\ \end{tabular} \\
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