I can't think about a query which intent will be double. Can you provide any example?
In my opinion you will surely have a common part of the query, which you can still optimize for but then you need to add the second part which is the one that identifies the page. In this case, considering that the intent is very closely related you want to ensure that the two pages are linked one to the other above the fold. You want to ensure to provide a link to your sales pages from the more informative one. That's useful and very much a must
Anyway if the two queries are really 100% matching, then you should try to merge the two pages by integrating the informative part with the commercial one.
Sorry to not be able to be more specific but I can't find a good example of queries that could face this issue.