The college has a 12:1 'ratio' between students and teachers. = The college's student-to-teacher 'ratio' is 12 to 1. [=for every 12 students, there is one teacher]
The office has a high 'ratio of' males to females. [=there are many more males that work at the office than females]
Women outnumbered men by a 'ratio of' three to two. [=for every three women, there were two men]
(..) How can you call yourself a scientist and run out of solder? Well, funny story. So, we have plenty of the / tin-to-lead ratio solder, but the spools look a lot like the / tin-to... Honey, honey, honey, let me stop you. That is-is not a funny story. (..)2016 TvShow: The Big Bang Theory Title: The Solder Excursion Diversion Season: 9 Episode 19