SOLUTION: 36. solve for n b) P(n,5)= 20P(n,3)

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Question 144475: 36. solve for n
b) P(n,5)= 20P(n,3)
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
P%28n%2C5%29+=+20P%28n%2C3%29
8nPr+5+=+20+%2A+8+nPr+3 ==>
8nPr+5+=+8%21%2F3%21+=+8+x+7+x+6+x+5+x+4+=+6720
8nPr3+=+8+x+7+x+6+=+336
so 20+%2A+336+=+6720
Therefore, 8nPr+5+=+20+%2A+8+nPr+3

P%28n%2C5%29+=+20P%28n%2C3%29 is true when n+=+8