Compound Possessive [duplicate]

Question

I am having problem understanding what the following sentence means exactly:

Bill's and my car had to be towed last night.

I can't quite figure out why the possessive is used in Bill's and what it means.

Answer 1

My car and the car of Bill had to be towed.

That's what it means. The possessive 's indicates what Bill possesses - the car.

So, saying: Bill's and my car had to be towed is the same as The car of Bill and my car had to be towed. You could also have said: Bill's car and mine had to be towed.

Answer 2

The sentence is somewhat ambiguous.

As written it means that you and Bill are the co-owners of a car that had to be towed.

But the speaker might be trying to say that both Bill's car and the his/her car had to be towed. If this were the case, the sentence should read:

Bill's car and mine had to be towed last night.

This becomes clear if you change the sentence to read:

Bill's and my wife were both ill after the meal.

Clearly, because both men cannot be married to the same wife, the speaker means to say that both wives were ill, and should have said:

Bill's wife and mine were both ill after the meal.

Using the plural raises other ambiguities, whether:

Bill's and my wives were both ill after the meal.

Or:

Bill's and my cars had to be towed last night.