Does 'days a week' need an apostrophe?

[susan_1981]

I do some transcription work, which often gets proofread, and they keep flagging it as wrong when I type, for instance, "3 days' a week" because they say it doesn't need an apostrophe, whereas I argue that it does because it's missing the word "of", so "3 days of a week". Who's right?

 

[Raymott]

"Three days a week" is correct. You don't need an apostrophe. Would you use one in "one day a week"? If your argument is correct (and I disagree that it is - where did you get that rule?), then why not use one there? How about in "three days per week" which means essentially the same?

"This substance costs 50 dollars an ounce." This means "50 dollars for one ounce". Would you put an apostrophe there? (No). We often leave out words, and we don't put apostrophes to show that.

 

[emsr2d2]

No apostrophe is required. The word "of" is not omitted because it was never required.

We use apostrophes in things like "I had three days' training" or "It's five minutes' walk from here".

 

[GoesStation]

We use apostrophes in things like "I had three days' training" or "It's five minutes' walk from here".

And we use them there because the words are possessives.