Singular subjects get a singular verb, right? And plural subjects get a plural verb. (We call this agreement.) So is the subject of this sentence singular or plural?
Let’s be technical: “1” is the subject of the sentence, and it’s a singular. “8 couples” is a plural, but it’s the object of the preposition “in.”
Now let’s be, um, poetic: “1 in 8 couples” obviously refers to a group of people, especially since we’re referring to a large population of people. We can be metaphorical and call the whole phrase the subject of the sentence semantically, right? So we could use a plural verb, right?
What do you think? Feel free to add something in the comments.
Here’s the picture from the article: