Final answer:
The markings on an LP-gas motor/mobile fuel container installed on a vehicle must be readable at all times. This ensures that the user can accurately determine the contents and important information about the fuel container.
Step-by-step explanation:
The markings on an LP-gas motor/mobile fuel container installed on a vehicle must be readable at all times. This means that the markings should not fade, smudge, or become illegible over time. The purpose of having readable markings is to ensure that the user can accurately determine the contents and important information about the fuel container, such as storage requirements and safety precautions.