Exegesis:

apokritheis ‘answering,’ cf. on 1.60.

ouchi hoi deka ekatharisthēsan ‘were not all ten made clean?’ ouchi implies an affirmative answer. hoi deka lit. ‘the ten’ views the group in its totality.

hoi de ennea pou ‘the (other) nine, where are they?’ pou is emphatic by position.

Translation:

Were not ten cleansed, or, where active voice is preferable, ‘didn’t I make ten (men/lepers) clean.’

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.