I think the example is perfectly clear. Classes that know spells and classes that prepare spells both rely on spell slots to determine what you can know/prepare, so there is no reason why the example wouldn't apply to both. Why should they have to spell it out for every single class?
Because there are people like my roommate who are very literal minded. Our conversation consisted of:
"They have an example for how many spells you know. But they are talking about rangers who only know a certain number of spells per level. That makes sense to me. But you use spell slots to determine which spells you prepare. I have 9th level spell slots. Why can't I prepare 9th level spells?"
"Because you determine spells you can prepare as if you were single classed."
"That's not what the example says, it says if you are a ranger you only know lower level spells. Which makes sense, because under ranger it says you only know a certain number of spells based on your ranger level."
"But the sentence above says that you determine your spells you both know AND prepare as if you were single classed."
"But that's my point. You determine your prepared spells by the level of spell slots you have. Not your level. A 1st level cleric who has 9th level spell slots can still cast 9th level spells."
"He can CAST them but he can't PREPARE them."
"Why not? He has 9th level spell slots and under cleric it says the maximum level you can prepare is the highest level spell slot you have."
"But the text says you determine which spells you prepare as if you were single classed. So if you were a singled classed level 1 cleric, you would only have level 1 spell slots."
"But the text never says 'Determine the spells slots you'd have if you were a level 1 cleric then use that to determine the maximum level spell you can prepare'."
"I think that's what 'Determine your known and prepared spells as if you were a single classed member of your class' means."
"If they meant that, you'd think they would have WROTE that. Instead they give us an example of the number of known spells you get as a Ranger. That was wasn't ambiguous to begin with because under Ranger it even says you use your Ranger level to determine spells known. There's nothing under Cleric stating you use your Cleric level to determine the number of spells you can prepare."
"That's true. Because it doesn't need to. Multi-classing is an optional rule and the rest of the text is written without really taking multi-classing into account."
"Well, that's stupid. They could have easily written that somewhere so we didn't have to figure out what they meant."