"A" is a singular article, meaning that there is only one of the thing being referenced.  One man plus one woman equals two total; as both men and woman are kinds of people, this means that there are two people total.  Riding a bike generally requires being on the bike in question.


Consider the staetement "An older man and woman ride bikes on the boardwalk near the ocean". Based on this statement, is "Two people are on bikes." a true statement? Yes/no/unknown