Question

Find the number of permutations of the first 8 letters of the alphabet taking four letters at a time.

a.1680
b.56
c.6720
d.109

Answer 1

The answer you are looking for is A.1608

Answer 2

Answer: a.1680

Explanation:

The number of permutations of n things taking m at a time is given by :-

`P^n_m=(n!)/((n-m)!)`

Similarly, the number of permutations of the first 8 letters of the alphabet taking four letters at a time will be :-

`P^8_4=(8!)/((8-4)!)\\\\=(8*7*6*5*4!)/(4!)\\\\=1680`

Hence, the number of permutations of the first 8 letters of the alphabet taking four letters at a time =1680