sentence to a 3 year's imprisonment

Hello: Anyone can tell me, which sentences are right? 

• There is a 3 months' probation.                                 --There is 3 month's probation.
• sentence to a 3 months' probation / imprisonment      --sentence to 3 months' probation / imprisonment 
• He is on a 3 months' probation / imprisonment.          --He is on 3 months' probation / imprisonment
• He is on a 3-month probation / imprisonment.            --He is on 3-month probation / imprisonment. 

Thanks

So follow this grammar, It is a 10-minutes meeting.=It is 10 minutes' meeting. right, teacher?

understand that, thanks so much.

Someone needs to help me.

It was a 10-minute meeting sounds totally normal.

What is the context for It's 10 minutes' meeting or It's a 10 minutes' meeting? Those don't sound normal at all! So I'm missing something.

It's a meeting of 10 minutes sounds grammatical, but not natural. But my mind doesn't rebel against it like the two above.

 

Grammar Geek wrote:

What is the context for It's 10 minutes' meeting or It's a 10 minutes' meeting? Those don't sound normal at all! So I'm missing something. It's a meeting of 10 minutes sounds grammatical, but not natural. But my mind doesn't rebel against it like the two above.

Hi GG

I was concentrating more on the genitive than the verb. However, if a goup of people has a 10-minute meeting every Monday morning, I might use the present tense to inform a new employee about the meeing and its duration: It's a 10 minutes' meeting. I didn't consider the tense to be the gist of the matter, and anyone can of course change it to whatever sounds better. I just wanted to give my opinion about the structures I think correct in such expressions:

It's a two-mile walk.
It's a two miles' walk.
It's two miles' walk.
It's a walk of two miles.

Cheers
CB