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Problem Solvin question

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Problem Solvin question

by jcovarrubiasu » Tue Jul 24, 2007 7:27 am
Hi, Can you help me find out how to aprouch this question?

All of the stocks on the over-the-counter market are designated 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 you the maximum number of different stocks that can be designated with these codes?

a) 2(26^5)


b) 26(26^4)


c) 27(26^4)


d) 26(26^5)


e) 27(26^5)

How should I approuch this problem?

I would think that because the there are 5 convination letters, each one of them with 26 letters of the alphabet. the answer is "B", However this is not true.

Thanks!
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Re: Problem Solvin question

by Sadowski » Tue Jul 24, 2007 7:29 am
jcovarrubiasu wrote:Hi, Can you help me find out how to aprouch this question?

All of the stocks on the over-the-counter market are designated 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 you the maximum number of different stocks that can be designated with these codes?

a) 2(26^5)


b) 26(26^4)


c) 27(26^4)


d) 26(26^5)


e) 27(26^5)

How should I approuch this problem?

I would think that because the there are 5 convination letters, each one of them with 26 letters of the alphabet. the answer is "B", However this is not true.

Thanks!
26^4+26^5 = 26^4(1+26) = 26^4 * 27 = C
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Re: Problem Solvin question

by jcovarrubiasu » Tue Jul 24, 2007 6:00 pm
What subject is this? convination, permutation, etc? I need practice. because that answer, I did not see it comming.
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by beny » Tue Jul 24, 2007 6:28 pm
Combinations (knowing how many combinations there are for 4-letter and 5-letter symbols) and Simple Algebra (distributive property).

The questions leans a lot more towards simple alebra than combinations (since you don't really need to know combinatins, just recognize that there are 26 potential matches per slot).
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by manred » Tue Jul 24, 2007 8:47 pm
The code could be either 4 lettered or 5 lettered.

First take 4 letter codes _ _ _ _. Each letter (blank) can be filled in 26 ways since there are 26 alphabets. So total no.of combinations is 26*26*26*26 = 26^4.

Similarly total no.of combinations for 5 digit codes is 26*26*26*26*26 = 26^5.

Total no.of codes = 26^4 + 26^5 = 26^4 (1+26) = 26^4 * 27.

Answer is C
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