Which masses (weights) must be applied in a ratio for the calculation of the maximum permissible towed load behind a truck (continuous brake system)?

You answered correctly. For calculating the maximum permissible towed load behind a truck with a continuous brake system, you must compare the permissible total mass of the truck to the actual mass of the trailer. This ratio ensures safety by considering the maximum load the truck is allowed to carry and the real weight being towed, which impacts braking and stability. The permissible total mass for both truck and trailer defines the legal limit, but you always need to use the actual mass of the trailer to reflect real-world conditions during the calculation. This prevents overloading and maintains safe operation on the road. Always remember: for the calculation, use the permissible total mass of the truck and the actual mass of the trailer.