SOLUTION: Using the definition of permutations and combinations, solve for n in the following equation. n P 3 = 2( n C 4)

Question 1083797: Using the definition of permutations and combinations, solve for n in the following equation.
n P 3 = 2( n C 4)
Answer by ikleyn(52784) (Show Source): You can put this solution on YOUR website!
.

n P 3 = n*(n-1)*(n-2).


n C 4 = .


So, your equation is 


n*(n-1)*(n-2) = .


Simplify (by canceling the factors n*(n-1)*(n-2) in both sides)


1 = ,   or


 = n-3  --->  n-3 = 12  --->  n = 15.

Answer. n = 15.

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