Factorial of n,n! :
The Combinations formula:
Important formulas on Combinations:
nc0 = 1
ncn = 1
ncr = ncn-r
The number of groups (combinations) of n different things taking any number at a time is:
nc0 + nc1 + nc2 +….. ncn = 2n – 1
- The number of ways (alternatively groups or combinations) in which n things can be divided into p things and q things is
- The number of ways (alternatively groups or combinations) in which 3n can be divided equally into three distinct groups each having n things is
- The number of ways (alternatively groups or combinations) in which 3n can be divided equally into three identical groups each having n things is
