Question 129657
P(n,r) = n!/(n-r)!]
C(n,r) = n!/[(n-r)!*r!]
---------
Evaluate:
a) P6,4 = 6!/2!=6*5*4*3 = 360
b) C7,2 = 7!/[5!*2!] = 7*6/1*2 = 21
c) P4,4 = 4!/(4-4)! = 4!/0!= 4! = 24
d) C9,0 = 9!/[9!*0!] = 1
=============
Cheers,
Stan H.