How should I properly write quotation marks and apostrophe in cases like the following ones?
There are five "McDonald's"s in our city.
All "7-11"'s in our town were opened within the last ten years.
How should I properly write quotation marks and apostrophe in cases like the following ones?
There are five "McDonald's"s in our city.
All "7-11"'s in our town were opened within the last ten years.
I don't see any reason to use quotation marks at all in your example sentences; you don't appear to be quoting something someone has said, and restaurant/convenience store names are not inherently written with quotation marks. In addition, the apostrophe is not appropriate in your second example; multiple 7-11s are plural, not possessive, and so you simply add the s without an apostrophe.
That said, here's an example to illustrate how you might use apostrophes and quotation marks together in a sentence where it makes sense:
We looked at the signs above each of the diners along the street; the one that read "Travis'" looked most inviting.
So yes, in this case you would place an apostrophe before a closing quotation mark. You're directly quoting the sign, so there's really no other option. It looks a bit odd, sure, so you might try to avoid it, but it's correct. Additionally if you use a font that distinguishes more clearly between apostrophes and quotes, it might be easier to read.