GmatPrep1?? (4 letter or 5 letter)

This topic has expert replies
Source: — Problem Solving |

Senior | Next Rank: 100 Posts
Posts: 60
Joined: Thu Jun 12, 2008 5:38 pm
Thanked: 2 times

by lvincy » Thu Sep 04, 2008 9:17 am
4 Character = 26X26X26X26 = 26^4
+
5 Character = 26X26X26X26X26= 26^5

=
26^4(26+1)
= 27(26^4)

Legendary Member
Posts: 1153
Joined: Wed Jun 20, 2007 6:21 am
Thanked: 146 times
Followed by:2 members

by parallel_chase » Thu Sep 04, 2008 9:18 am
this is a permutation problem.

26 letters

4 letter code - 26*26*26*26 = 26^4

5 letter code - 26*26*26*26*26 = 26^5


total permutations = 26^4 + 26^5 = 26^4 (1+26)

=> (27) 26^4

Hope its clear.