A. The factorial
symbol n! indicates the product of all positive integers from 1 to n.
Therefore:
6! = 1 x 2 x
3 x 4 x 5 x 6 = 720
B. The
formula for permutation is:
P = n! / (n –
r)!
The given
value is 6P5 which is the form nPr. Therefore,
P = 6! / (6 –
5)!
P = 720 / 1
P = 720
C. The
formula for combination is:
C = n! / r! (n
– r)!
The given
value is 12C3 which is the form nCr. Therefore,
C = 12! / 3!
(12 – 3)!
C = 12! / 3!
9!
Where 12!
can be written as 12! = 9! x 10 x 11 x 12
C = 9! (10 x
11 x 12) / 3! 9!
Cancelling
9!:
C = 10 x 11
x 12 / 3!
C = 1,320 /
6
C = 220
