Hi, a problem was posed to me yesterday and I simply cannot put it to rest!
The phrase "Seven days notice" has me baffled as to its punctuation. At first I thought it correct to follow the basic rule of possessive time, which leaves "days'" as the possessive noun. However I can also see that "day" is not a measure of time; and could be construed as a quantitative descriptor of notice.
If anyone can help me validate either argument I would very much appreciate your input.
It's more usual to put the apostrophe after days, in official documents, etc., e.g.
1. ...ten days' notice...
= "notice of ten days [in duration]".
Some might argue that we can treat "ten days" as an attributive noun phrase, and omit the apostrophe:
2. ...ten days notice...
But when we use phrases of time attributively, we're more likely to say e.g.
3. ...a ten-year sentence...
4. ...a ten years sentence...