Have you heard how many hours she spends studying daily?
ーDid you hear how much she studies ever day?
「彼女が毎日どのくらい勉強するが聞きましたか?」
Did you hear how much ...? のように聞けます。
ーHave you heard how many hours she spends studying daily?
「彼女が毎日何時間勉強に費やすか聞きましたか?」
Have you heard how many hours ... ? のようにも聞けます。
ご参考まで!