Of the 9 students on Lincoln High School’s Debate Team, 4 will be chosen to represent the school at Regionals. How many different groupings could be chosen?
it is not a ratio. it is a combination, written ncr. The math for it is n!/((n-r)!*r!) or in your case, 9!/(5!*4!)
this comes out to be 126. I hope this is helps.