Using the word "apart"

Question

A doctor says " you have to take this medication 3 times a day" Does the following questions ok to be asked ? ( Grammatically speaking )

1-How many hours apart are there between each time ?

2- There are three hours apart between each time.

Answer 1

What you are describing is the interval:

[Merriam-Webster]
1 a: a space of time between events or states

So:

"Take this medication 3 times a day."
"Do you mean at 8-hour intervals?

Or:

"What is the interval between doses?"

Note, too, the use of dose in the second example.

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I'm not certain if either of the sentences in the question is technically ungrammatical (in violation of actual grammar rules), but they are both at least awkward and not how people would typically phrase them.

The main problem is the use of each time rather than something like dose. Also, pairing apart with between is redundant.

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If you don't want to use interval (or dose), and keep the sentences as close to the original as possible without them sounding quite strange, the following might be used:

"How many hours apart should I be taking the medicine?"
"How many hours should there be between the times I take it?"
"Take the medicine every three hours."

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After a series of comments, it's been brought to my attention that it might be considered unusual to use the word apart or between with a singular noun, even in context.

In short:

• ✔ How many hours are there between doses.
• ？ How many hours are there between each dose.

While the singular form has always been colloquial and idiomatic in my own use and experience in Canada, it seems it's unusual in other places. To me, the singular version actually sounds more natural—although I have no problem with the plural version, and would probably use it in strictly formal writing.

Although it would be understood, those who aren't used to the singular version could pause upon hearing it.

So, using the singular version seems to be normal in some places, but uncommon, and a little odd, in others.