Explanation:

- The speed ratio of two scooters is given as 9:5.

- The second scooter travels 75 km in 6 hours.

- Calculating the speed of the second scooter: Speed = Distance / Time = 75 km / 6 hours = 12.5 km/h.

- The second scooter's speed is 5 parts (according to the ratio).

- The first scooter's speed corresponds to 9 parts (according to the ratio).

- Using cross-multiplication: (Speed of first / Speed of second) = 9 / 5, thus, Speed of first = (9/5) * 12.5 = 22.5 km/h.

- The options provided are 12.5, 22.5, 11.5, 10.5 km/h.

- Option 2: 22.5 km/h matches the calculated speed for the first scooter.

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