the average British and Russian family/families has/have

[Boris Tatarenko]

I'm not sure which one is correct.

The average British and Russian family/families has/have someting in common.

I think the bold options are correct.
What would you say?

Thanks in advance.

 

[Rover_KE]

I agree.

 

[emsr2d2]

Interesting. I would use "The average British and Russian family has ...". I would assume that many families have been considered and one single average example of each has been found. Despite the fact that the sentence is talking about one English family and one Russian family (which I realise means it's talking about two families and therefore the plural could be argued), I find it much more natural to think of it as "An average British family, like an average Russian family, has ..."

 

[Tdol]

I think both forms work.

 

[Roman55]

I am not a teacher.

I think the singular in something like 'The average British and Russian family has 2.4 children' is OK, but not in Boris's sentence.

Here he's saying they have something in common (with each other). It sounds incomplete to say, 'The average British and Russian family has something in common.' With what?

 

[MikeNewYork]

The "what" may have come in a previous sentence or may come in a subsequent sentence. There is no rule that says all information must be contained in a single sentence.