SOLUTION: If nC12 = nC8, find out what n is.

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Question 920288: If nC12 = nC8, find out what n is.
Found 2 solutions by richard1234, Edwin McCravy:
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
n = 20

Note: nCk = nC(n-k)

Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
Use the fact that

 nCr = nC(n-r)

nC12 = nC8

Comparing those, you get the two equations:

r=12
n-r=8

Substitute 12 for r in the second one

n-12=8
   n=20

Checking with a TI-84 calculator:

nC12 = nC8

20C12 = 20C8

125970 = 125970

Edwin