"Are you ill?"

Translation: Apakah kamu sakit?

[Kauakolo]

can you say sakitkah kamu?

[Rizadikur]

You can. But it is rarely used.

The most common informal phrase is "Kamu sakit ya?"

[Aleksandro_RU]

Why is the question without apakah?

[Hans_Se]

You can use "Apakah" in this case ... both have same meaning

[Lisa-Lisa-Lisa]

why do you not need berapa in this instance?

[INalsGio]

Berapa is "how many" or "how much", it has nothing to do with a yes or no question, the conjunction you may be thinking is "apakah", which can, but is not required to, be used here.

[Lescol123]

to indicate a question is being asked - I think apakah or apa is needed in this example