YOU SAID:

if i go to sleep right now and wake up at seven at night how many hours will i have slept?

INTO JAPANESE

もし私が今すぐ寝て、夜7時に目を覚ますと、私は何時間寝ているだろうか?

BACK INTO ENGLISH

If I go to bed now and wake up at seven o'clock, how many hours have I slept?

INTO JAPANESE

今寝て7時に起きたら、何時間寝たの?

BACK INTO ENGLISH

How long did you go to bed if you got up at 7 o'clock?

INTO JAPANESE

7時に起きたら、どのくらい寝ましたか。

BACK INTO ENGLISH

How long did you go to bed when you got up at seven?

INTO JAPANESE

7時に起きたとき、あなたはどのくらい寝ましたか。

BACK INTO ENGLISH

How long did you go to bed when you got up at seven?