Good morning (here). I'm writing a scientific paper on Container Loading Problems, and I want to make the difference between two different instances, which consisit in filling the container with 24 and with 72 boxes. So my question is: Could I change "The (mathematical) analysis was conducted on two problems: a 24 box one and a 72 box one" for "The (mathematical) analysis was conducted on two problems: a 24 and a 72 box one" ? Or should I say "a 24 and a 72 box ones"

That doesn't really fit and we have no idea of what context you have provided the reader. Why don't you just say something like "The analyses were of containers loaded with 24 boxes and also with 72 boxes?"

Well, here I go with a clearer context: The problem instances used to test the proposed heuristic procedure were generated as follows: a series of items go before the one I want to check - item ... - item ... - One problem instance was generated for each box size configuration in order to perform the qualitative and integration analysis only on two problems: a 24 box one and a 72 box one. I would say that in this context your rephrasal moves away from the mathematical notion that the sentence wants to communicate. But, how about this? - One problem instance was generated for each box size configuration in order to perform the qualitative and integration analysis only on a 24 and a 72 box problems. Again, I have doubts with the final S.

It sounds as though you're more concerned with jargon, wordiness and inflated language than with straightforward, understandable English, but try: "24- and 72-box problems."

Thankyou, sd, both for your call of atention and for your help with my language doubt. Part of this quest for eloquency has to do with the fact that all along the paper these two problems are named as "the 24 box problem" and "the 72 box problem". Also, this is a modeled mathematical scenario, so I cannot talk about actual "loaded containers" Regarding your last sugestion, I think we're getting closer to the point, but "24 and 72 box problems" makes it a general statement about those types of problems. But the point here is about the specific 24 and 72 box problems dealt with in the paper. That is what the phrase "a 24 and a 72 box problems" wants to get across. Besides, is it so "inflationary" to want to be as synthetic as possible? This is a doubt I've always had in English, and in many ocassions I've got around. Today, I would just like to clear how to deal with the plural s when you have two singular things with something in common.

I think both patent and legal language also qualify for that comment. What they have in common is an attempt at bulletproofing against ambiguity. That spirit is partly what led to this question in the first place. I agree with your suggestion for the second of the instances below