Let me guess, Catholic school? Actually, now that I think about it, it's an insult to the most devout of Catholics to consider that a "guess". Of course it's a Catholic school. What other type of school would use arithmetic to try to push it's antiquated agenda through the guise of word problems?
Honestly, I'm not even hating on the question. Any place other than a Catholic school and I would be appalled by then inappropriateness of that unnecessary insert, but at a Catholic school it's just called integrating lesson plans. A little two birds, one stone action. Hey, these kids had to learn how to manipulate statistics just like they had to learn that loving someone of the same sex automatically makes your impending afterlife experience a little more...well...humid. Might as well use the former to hammer home the latter.
Plus, it's pretty clear the situation presented is strictly hypothetical. 70% of the men in town married? 90% of the women in town married? Yeah, maybe in 1971. In 2016 we have this thing called a divorce rate and I'm pretty sure it's currently a number that resides somewhere in the middle of both those percentages. If we were really looking to be lenient then we could give this teacher the benefit of the doubt, because this place where everyone is joined happily in holy matrimony is clearly a fantasy land. An overly conservative fantasy land where gays are shunned, but a fantasy land where men and women never grow tired of each other's bullshit. Since that clearly doesn't exist I think we can just consider every aspect of this question fabricated, and not at all a sign that the person that came up with it needs to be put out to pasture.