Answer: 0.69 m/ mile.
Step-by-step explanation:
The altitude gradient between two cities X and Y =

Given: Two cities are separated by 200 miles.
City X has an altitude of 122 meters.
City Y has an altitude of 260 meters.
The altitude gradient between two cities X and Y =

Hence, the altitude gradient between the two cites = 0.69 m/ mile.