Explanation:

- Let's denote the speed by "S" km/hr.

- Aman travels 180 km at speed S. Time for 180 km = 180/S hours.

- He then travels \((3 \times 180) - 180\) km, which is 360 km more.

- Time for 360 km = 360/S hours.

- Total time = (180/S) + (360/S) = 540/S hours.

- He took 36 hours for the whole journey.

$$

\text{Equation: } \frac{540}{S} = 36

$$

- Solve for S:

- Multiply both sides by S: \(540 = 36S\)

- Divide by 36: \(S = 15 \, \text{Km/hr}\)

- Correct Answer: Option 1, 15 Km/hr