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Probability

by sq720 » Mon May 11, 2009 5:49 am
All the stocks on the over- the counter market are designed by either a 4 letter or a 5 letter code that is created by using the 26 letters of the alphabet. Which of the following gives the maximum numbers of different stocks that can be designated with these codes?

2(26^5)
26(26^4)
27(26^4)
26(26^5)
27(26^5)

Ans C
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by gauravgundal » Mon May 11, 2009 7:10 am
To find the max.

4 letter Code from 26 alphabet can be obtained = 26*26*26*26

and

5 letter Code from 26 alphabet can be obtained = 26*26*26*26*26

Thus the answer obtained from above results = 26^4 +26^5
=27(26^4)
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by Mr2Bits » Mon May 11, 2009 7:46 am
gauravgundal wrote:
Thus the answer obtained from above results = 26^4 +26^5
=27(26^4)
Is there a formula or rule for this methodology?
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by mike22629 » Wed May 13, 2009 5:27 am
Its come down to factoring.

26^4 + 26^5 = 26^4(1+26) - not that you take 26^4 out of both terms

Hence = (27)26^4
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