Maximum number of combinations

I have 36 households and 429 vehicles.

Of the households 15 can have two vehicles, while the others can only have one vehicle.

I iterate and combine households: 2 at a time, 3 at a time... 36.

What is the maximum number of combinations of households and vehicles?

Answer: "The maximum number of combinations is reached when combining X households with 429 vehicles: (NumberofCombinations)"