Minutes' work or minutes of work

Question

If, for example, a teacher was asking their students to continue working for 30 minutes, would it be grammatically correct for them to say "do thirty minutes' work" or would they have to say "do thirty minutes of work"?

Thanks.

Answer 1

The second is quite acceptable.

The first is acceptable; perhaps you are worried that the 's construction should be confined to true possessives, rather than associatives. If so, you're not alone. There is a move advocating the dropping of the apostrophe of the apostrophe-s as an associative rather than a possessive marker. Hence 'writers guild', 'dogs home', 'We bought the children's clothing at the childrens clothing department at Morse Bros.'

If you want an example that's closer to home (and from an apparently reputable source):

Pitt, David (1970). Tradition and economic progress in Samoa: A case study of the role of traditional social institutions in economic development. Oxford University Press. ISBN 0-19-823156-3. "(...) findings generally agree on an average of about 28-30 hours work per week for an adult male village worker."

You can examine the different stances on this issue in some of these articles and this thread.

Answer 2

Spend thirty more minutes doing something.

What did you fill your thirty minutes with?

I filled it with thirty minutes of work.