SOLUTION: In math class, there are 24 students. The teacher picks 4 students to help do a demonstration. How many different groups of 4 could she have chosen?

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Question 782261: In math class, there are 24 students. The teacher picks 4 students to help do a demonstration. How many different groups of 4 could she have chosen?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Assuming order doesn't matter, then...


n C r = (n!)/(r!(n-r)!)

24 C 4 = (24!)/(4!*(24-4)!)

24 C 4 = (24!)/(4!*20!)

24 C 4 = (24*23*22*21*20!)/(4!*20!)

24 C 4 = (24*23*22*21)/(4!)

24 C 4 = (24*23*22*21)/(4*3*2*1)

24 C 4 = (255024)/(24)

24 C 4 = 10626


Assuming order doesn't matter, then there are 10626 different groups.