SOLUTION: How do I solve the following problem? Evaluate P(7,3). Thanks for your help.

Algebra ->  Permutations -> SOLUTION: How do I solve the following problem? Evaluate P(7,3). Thanks for your help.      Log On


   

Question 224816: How do I solve the following problem?
Evaluate P(7,3).
Thanks for your help.
Answer by LtAurora(115) About Me  (Show Source):
You can put this solution on YOUR website!
The equation for P is n%21%2F%28n-r%29%21, which is used to order a collection of n elements taken at r time.
The n in our case is 7, and the r is 3.
So, we have the number of permutations of 7 taken 3 at a time.
P(7,3)=7%21%2F3%21
This gives us: %287%2A6%2A5%2A4%2A3%21%29%2F%283%21%29
The 3%21 cancel to leave us with:
7%2A6%2A5%2A4
Which is: 840