Three out of every four automobile owners in the U.S also own a bicyle

You have it right, but your sentences are missing periods.  Also, I think "US" is correct, but if you place a period after one letter (abreviation) you should also place one after the other.

I suppose you could argue that "Three people own bicycles," is correct.  Actually, your version sounds more natural to my ear.  (own and owns are definitely correct)

On the other hand, someone else might argue that "Three people own bicycles," means that each of the three owns multiple bicycles.

Beats the heck out of me!  Help!

  - A.

Kprasadreddy

Three out of every four automobile owners in the U.S also own a bicyle

One out of every four automobile owners in the U.S also owns a bicyle

Kprasadreddy

Thanks but can you explain the grammar behind it?

In your first example, "three" is the subject of the sentence.  The prepositional phrase "out of etc." modifies "three."  The plural subject requires the plural verb, "own."

The subject of your second sentence is "one," which is singular and takes the singular verb "owns."

The separate issue, "bicycle(s)," is something I'm not sure about.  If you say "'Three people own a bicycle," it could be interpreted to mean that they all share in the ownership of a single bicycle. In the present example, context would rule that out; but "Three people own bicycles," could mean that A owns one, B owns one, and C owns five   -  equals seven bicycles all together.  (You might argue that that doesn't matter.)

Best regards,  -  A.