Given that,
5 machines make 5 articles in 5 minutes.
So it implies that, it takes 5 minutes for a machine to make 1 item.
So, when there is 100 machines, each machine needs 5 minutes to make one article.
So each machine does,

That is, 20 articles will be produced per minute when there is 100 machines. So for total of 100 articles,

5 minutes is needed for 100 machines to make 100 articles.