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by thephoenix » Thu Feb 11, 2010 9:13 pm
it sud be 26C1+26^2+26^3=18278

for 1 letter code no. ways for selection=26
for 2 letter code since rep is allowed=26*26
for 3 letter coide since rep is allowed=26*26*26

totl=26+26*26+26*26*26=18278
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by papgust » Thu Feb 11, 2010 9:13 pm
Please take some effort to search for the post before a start a new topic! Here it is,

https://www.beatthegmat.com/alphabet-cod ... t6108.html
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by Osirus@VeritasPrep » Thu Feb 11, 2010 9:16 pm
I got 2951 choice A

I did it Manhattan's way

The total number of 3 letter stocks would be

26!/(23! * 3!)

The total number of 2 letter stocks would be

26!/(24! * 2!)

The total number of 1 letter stocks would be

26!/(25! * 1!)

You would add each up which would be

2600 + 325 + 26 = 2951

Choose A
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by thephoenix » Thu Feb 11, 2010 9:27 pm
osirus0830 wrote:I got 2951 choice A

I did it Manhattan's way

The total number of 3 letter stocks would be

26!/(23! * 3!)

The total number of 2 letter stocks would be

26!/(24! * 2!)

The total number of 1 letter stocks would be

26!/(25! * 1!)

You would add each up which would be

2600 + 325 + 26 = 2951

Choose A
hey for this question the method u used is wrong bcoz
as per q
AA is a code
so for first position we have 26 choices and for second position we again have 26 choices (repetetion is alowed)
your method wud have ben correct if repetetion is not allowed
same is true for 3 letter code
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