We’ve got cake and cookies for the party. There’ll be cake and cookies at the party.
Like @Southernboy, I’d go with “How much for the coffee? How much for the tea?”, or “How much for the coffee and the tea?” However, that last question isn’t going to be that common - do you often see a situation when someone wants to pay for a coffee and a tea?
As an example, I think you’d say “Cake and cookies is delicious” if you meant a combination of the two, thus forming a single food item, and “Cake and cookies are delicious” if you meant them separately. Maybe “There are cookies and cake…” would be less jarring.
There is one person waiting. There are three persons* waiting.
As for your question, cake is an interesting noun. [Perhaps @nz can chime in.]
One cake is made of all the pieces of cake that are inside of it, yes?
In this case “some” indicates an amount. We don’t know how many slices are left, but we know it [the cake] is not gone.
Because a cookie is essentially a single serving cake, there is not some cookie, there is a cookie, or there are some cookies. More than zero, less than infinity.
Sorry, went crazy there, hope this helped.
*persons is technically OK, ‘people’ is more appropriate, but I wanted to keep it simple for the example
EDIT I never answered the question, lol. I would treat cake and cookies as a single set of desserts, so, I would say “there is some cake and cookies”
Even in those cases though, wouldn’t you just ask “How much?”, or “How much for the drinks?”
It could happen, sure, but it seems pretty unusual. If I have a coffee and my wife has a tea, and we have nothing else, and we’re with a group, and we’re trying to figure out the bill, yeah I suppose - but that’s not something that happens often.
Underlying point: I think we often construct sentences to avoid slightly odd grammar issues like this one, where both options sound a bit off. I certainly do this consciously when I’m writing. I suspect I also do so when speaking.
They are both correct, but some people are sticklers ( polite word for “assholes”) about one or the other.
You can use the plural rule: Use ‘are’ because you are talking about a list composed of more than one thing.
Or
You can use the proximity rule: The first item you are referring to is singular, and so should be referred to with ‘is’.
A good rule of thumb to remember is “anyone who cares about this is anal-retentive.”
This is because “cake and cookies” is treated as a plural subject. Even though “cake” is singular, the addition of “cookies” makes it plural, so you need the plural verb “are.”
How much is the coffee and the tea?
When referring to a pair of things like coffee and tea as a general idea (not focusing on each individually), you treat it as a singular entity, hence the singular verb “is.”