Explanation:

- The person covers equal distances at three different speeds: 5 km/h, 8 km/h, and 10 km/h.

- Let's assume the distance covered at each speed is 'd' km.

- The time taken to cover distance 'd' at 5 km/h is \( \frac{d}{5} \) hours.

- The time taken at 8 km/h is \( \frac{d}{8} \) hours.

- The time taken at 10 km/h is \( \frac{d}{10} \) hours.

- The total time for all three distances is \( \frac{d}{5} + \frac{d}{8} + \frac{d}{10} = 2 \text{ hours and } 33 \text{ minutes} \) or \( \frac{153}{60} = \frac{51}{20} \) hours.

- Solving \( \frac{d}{5} + \frac{d}{8} + \frac{d}{10} = \frac{51}{20} \) gives \( \frac{49d}{40} = \frac{51}{20} \).

- Solving for d, we find \( d = 6 \).

- The total distance is \( 3d = 18 \text{ km} \).

So, the correct answer is:

Option 1: 18 km

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