# Permutation or Combination?

• Mar 14th 2009, 07:39 PM
puzzledwithpolynomials
Permutation or Combination?
A varsity volleyball team needs nine members. Of these nine members, at least fivev must be seniors. How many of the possible groups of juniors and seniors have at least five seniors?

My reasoning:
A combination must be used because order doesn't matter. 9 Cr 4=126

Yes or no?
• Mar 14th 2009, 07:46 PM
e^(i*pi)
Quote:

Originally Posted by puzzledwithpolynomials
A varsity volleyball team needs nine members. Of these nine members, at least fivev must be seniors. How many of the possible groups of juniors and seniors have at least five seniors?

My reasoning:
A combination must be used because order doesn't matter. 9 Cr 4=126

Yes or no?

Yes
• Mar 14th 2009, 07:51 PM
Jhevon
Quote:

Originally Posted by puzzledwithpolynomials
A varsity volleyball team needs nine members. Of these nine members, at least fivev must be seniors. How many of the possible groups of juniors and seniors have at least five seniors?

My reasoning:
A combination must be used because order doesn't matter. 9 Cr 4=126

Yes or no?

note that it says "at least" 5 seniors. meaning the team can have 5 or 6 or 7 or 8 or 9 seniors. were we told from what size groups of people we are choosing from? how many seniors? how many juniors?