Convert to a common denominator (tenths), then add.<br><br>
&bull; \(\frac{4}{5} = \frac{8}{10}\)<br>
&bull; \(\frac{9}{10} + \frac{8}{10} = \frac{17}{10}\)<br>
&bull; Convert to a mixed number: \(\frac{17}{10} = 1\frac{7}{10}\)<br>
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Final Answer: C: \(1\frac{7}{10}\) km