thirty not wanting to be taught

[wowenglish1]

I would like to know the meaning of the next sentence.

For every person wishing to teach, there are thirty not wanting to be taught.

[5jj]

If the number of people who wish to teach is x, the number of people who do not wish to be taught is 30x.
Class sizes in Britain tend to be about 30. The writer is jokingly suggesting that in every classroom there is one teacher with 30 reluctant pupils.