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hard time understadning the question

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hard time understadning the question

by ildude02 » Fri Jul 04, 2008 12:44 pm
For a finite sequence of non zero numbers, the number of variations in the sign is defined as the number of pairs of consecutive terms of the sequence for which the product of the two consecutive terms is negative. What is the number of variations in sign for the sequence -1, -3, 2, 5, -4 ,
-6.

1)1
2)2
3)3
4)4
5)5

BTW, can anyone tell me how to copy the questions from a gmat prep screen? I try to right click on the screen when I'm reviewing the question, but I don't get any options to even try to copy the page. I wonder how to copy the question from the prepr screen. Appreciate it.
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Re: hard time understadning the question

by parallel_chase » Fri Jul 04, 2008 2:01 pm
ildude02 wrote:For a finite sequence of non zero numbers, the number of variations in the sign is defined as the number of pairs of consecutive terms of the sequence for which the product of the two consecutive terms is negative. What is the number of variations in sign for the sequence -1, -3, 2, 5, -4 ,
-6.

1)1
2)2
3)3
4)4
5)5

BTW, can anyone tell me how to copy the questions from a gmat prep screen? I try to right click on the screen when I'm reviewing the question, but I don't get any options to even try to copy the page. I wonder how to copy the question from the prepr screen. Appreciate it.
I think the the answer is 2, according to me the problem says that in a given sequence variation is defined when two consecutive terms are multiplied and the yield is negative. In the sequence only (-3, 2) and (-4,5) are consecutive and results in negative when multiplied.

Whats the OA?

Coming to your other question:

I dont know about mac but on a PC can you see a print screen button. Hit that button once, open paint brush software in accessories. press CTRL V and save it as JPG.
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by ildude02 » Fri Jul 04, 2008 3:02 pm
What's the logic behind considering -3 and 2 as consecutive terms? The answer is not 2.

I use PC, but I don't see a print screen button on the screen. I wonder how come I don't see the "print" screen. All I see, check answer, correct answer and flag for review.
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by parallel_chase » Fri Jul 04, 2008 3:17 pm
ildude02 wrote:What's the logic behind considering -3 and 2 as consecutive terms? The answer is not 2.

whats the answer is it 1

I use PC, but I don't see a print screen button on the screen. I wonder how come I don't see the "print" screen. All I see, check answer, correct answer and flag for review.
I am sorry, my bad. On the keyboard. It should say "prt sc" if you are using a notebook.
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by ildude02 » Fri Jul 04, 2008 3:53 pm
thanks for your input about how to copy the screen. It did work, but do I have to exit from the review every time I have to copy it into a word doc? I say that since the review screen never lets me view any other application unless I exit of the review scree. Not sure if there is any way around it?

As for the answer, it's 3. It's a gmat prep question. From the sequence, I was literally looking for concesutive terms before I can pair them, so I started arranging them in a consecutive pattersn but then found zero variations. May be we need to consider the terms as given int he question as consecutive
( though clearly 1, -3, 2, 5 etc are not consecutive). In doing so, I can see three pairs which gives a negative sign.

(1, -3), (-3, 2) and (5, -4). The other pairs(2, 5) and (-4, -6) dont satify the variations definition. Can anyone find better reasoning behing this question?
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Re: hard time understadning the question

by Stuart@KaplanGMAT » Fri Jul 04, 2008 9:43 pm
ildude02 wrote:For a finite sequence of non zero numbers, the number of variations in the sign is defined as the number of pairs of consecutive terms of the sequence for which the product of the two consecutive terms is negative. What is the number of variations in sign for the sequence -1, -3, 2, 5, -4 , -6.

1)1
2)2
3)3
4)4
5)5

BTW, can anyone tell me how to copy the questions from a gmat prep screen? I try to right click on the screen when I'm reviewing the question, but I don't get any options to even try to copy the page. I wonder how to copy the question from the prepr screen. Appreciate it.
If the question is posted correctly, the answer should most definitely be 2.

The question doesn't refer to consecutive numbers, it refers to consecutive terms.

In this sequence, we have the terms:

n1 = -1
n2 = -3
n3 = 2
n4 = 5
n5 = -4
n6 = -6

The only way we get a negative product is if we multiply a positive by a negative. There are 5 possible products of consecutive terms:

n1 * n2 = +3
n2 * n3 = -6
n3 * n4 = +10
n4 * n5 = -20
n5 * n6 = +24

Exactly two of the products are negative.

Looking at your last post, you cited n1 = 1 instead of n1 = -1. If, in fact, the first term is supposed to be +1, then the answer would be 3, since:

n1 * n2 = -3,

giving us a third negative product.
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by ildude02 » Sat Jul 05, 2008 7:32 am
my bad, I just realized I copied -1 instead of 1. Thanks for the posts.
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by vladmire » Wed Dec 24, 2008 7:58 am
What does number of variations in sign for the sequence mean?
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by Stuart@KaplanGMAT » Wed Dec 24, 2008 8:02 am
vladmire wrote:What does number of variations in sign for the sequence mean?
From the question stem:
For a finite sequence of non zero numbers, the number of variations in the sign is defined as the number of pairs of consecutive terms of the sequence for which the product of the two consecutive terms is negative.
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by dubeystuts » Sun Feb 01, 2009 6:27 am
I am really sorry but I still don't understand the question completely. Can someone please explain the question and how to get the answer in bit more details?
Many thanks for your time and help.
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by aroon7 » Sun Feb 01, 2009 8:53 am
I got this question in yesterday's test
the sequence is:
1,-3,2,5,-4,-6

ildude02 did a typo...
so the answer is 3
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by dubeystuts » Sun Feb 01, 2009 2:38 pm
My problem is i dont understand the question. Can someone please explain? Your help is much appreciated.
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by gabriel » Tue Feb 03, 2009 4:17 pm
dubeystuts wrote:My problem is i dont understand the question. Can someone please explain? Your help is much appreciated.
A change from - to + or from + to - . Now in the sequence given count how many times the sign changes.
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by ellexay » Tue Feb 03, 2009 6:22 pm
Don't worry about the "variations in sign" term. Look at it like a "definition" question...i.e., pretend it's asking what is 4%%5 if %% means 4-5.
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by dubeystuts » Sat Feb 07, 2009 9:04 am
Thanks a lot guys.
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