Question 35541
Easier formula to remember and use:  

5P2 means a permutation of 5 things taken 2 at a time.  Start with the first number (which in this case is 5), and count down for a total of 2 numbers:

5P2 = 5*4 = 20


No extra charge for a few more:


5P3 means to start with 5 and count down for a total of 3 numbers:
5P3 = 5*4*3 = 60


7P1= 7
7P2 = 7*6 = 42
10P2= 10*9=90
10P3 = 10*9*8 = 720
11P2= 11*10 = 110
6P4 = 6*5*4*3 = 360
etc.


Isn't that simple??


R^2 at SCC