VeritasPrepKarishma wrote:

kt00381n wrote:

Please explain this problem..Thank you

There are two slightly different ways of doing this question:

No of different four letter codes:

26*26*26*26 = 26^4

No of different five letter codes:

26*26*26*26*26 = 26^5

Total number of codes = 26^4 + 26^5 = 27*26^4

or

Total no of different four or five letter codes:

26*26*26*26*27 = 27*26^4

(you multiply by 27 because for the last letter, you have 27 different possibilities - the 26 letters and null i.e. no letter which takes care of including all the 4 letter codes)

Thank you karishma

I guess some assumptions in the question are that letters can be repeated

so we can have a code like AAAA and BBBBB or AAAA and AAAAA

looking forward to more assistance from you , thank you

_________________

- Stne