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Of the 800 sweaters in a certain store, 150 are red. How

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Of the 800 sweaters in a certain store, 150 are red. How  [#permalink]

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New post Updated on: 23 Apr 2012, 20:47
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Of the 800 sweaters in a certain store, 150 are red. How many of the red sweaters at the store are made of pure wool?

(1) 320 of the sweaters at the store are neither red nor made of pool wool

(2) 100 of the red sweaters at the store are not made of pure wool

Originally posted by jairus on 05 Feb 2009, 06:12.
Last edited by Bunuel on 23 Apr 2012, 20:47, edited 1 time in total.
Edited the question and the OA
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Re: Of the 800 sweaters in a certain store, 150 are red. How  [#permalink]

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New post 23 Apr 2012, 21:03
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MBADreamzzz wrote:
Why do we assume no other material could be used to make the red sweaters? Why wouldn't 40 of the remaining sweaters be polyster instead of pure wool?

In that case wouldn't E be the appropriate answer?


Actually we do not assume that. All sweaters in the world are either wool or NOT wool (any other material). Look at either of the diagrams below, there is a row saying "Not Wool", so all sweater out of 800 which are made of some other material than wool are distributed there.

Of the 800 sweaters in a certain store, 150 are red. How many of the red sweaters at the store are made of pure wool?

(1) 320 of the sweaters at the store are neither red nor made of pool wool:
Attachment:
(1).png
(1).png [ 6.68 KiB | Viewed 15310 times ]
Not sufficient to get # of red sweaters made of pure wool (yellow box).

(2) 100 of the red sweaters at the store are not made of pure wool:
Attachment:
(2).png
(2).png [ 6.3 KiB | Viewed 15307 times ]
As you can see, # of red sweaters made of pure wool (yellow box) is 150-100=50. Sufficient.

Answer: B.

Hope it's clear.
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Re: DS sets  [#permalink]

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New post 11 Apr 2011, 11:31
jairus wrote:
Of the 800 sweaters in a certain store, 150 are red. How many of the red sweaters at the store are made of pure wool?

1) 320 of the sweaters at the store are neither red nor made of pool wool

2) 100 of the sweaters at the store are not made of pure wool


1) no information to come with pure wool red sweaters
2) 150-100= red pure wool sweaters
Ans. B.

What is the correct answer? please help.
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Re: DS sets  [#permalink]

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New post 11 Apr 2011, 11:51
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Baten80 wrote:
jairus wrote:
Of the 800 sweaters in a certain store, 150 are red. How many of the red sweaters at the store are made of pure wool?

1) 320 of the sweaters at the store are neither red nor made of pool wool

2) 100 of the sweaters at the store are not made of pure wool


1) no information to come with pure wool red sweaters
2) 150-100= red pure wool sweaters
Ans. B.

What is the correct answer? please help.


I believe there is a problem in this question:
1) 320 of the sweaters at the store are neither red nor made of pool wool
This means that there are at least 320 NOT PURE WOOL sweaters.

2) 100 of the sweaters at the store are not made of pure wool
This tells are that AT MOST 100 sweaters at the store are NOT PURE WOOL sweaters.

Two contradicting statements.

I may be wrong.
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Re: DS sets  [#permalink]

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New post 11 Apr 2011, 16:35
fluke wrote:
Baten80 wrote:
jairus wrote:
Of the 800 sweaters in a certain store, 150 are red. How many of the red sweaters at the store are made of pure wool?

1) 320 of the sweaters at the store are neither red nor made of pool wool

2) 100 of the sweaters at the store are not made of pure wool


1) no information to come with pure wool red sweaters
2) 150-100= red pure wool sweaters
Ans. B.

What is the correct answer? please help.


I believe there is a problem in this question:
1) 320 of the sweaters at the store are neither red nor made of pool wool
This means that there are at least 320 NOT PURE WOOL sweaters.

2) 100 of the sweaters at the store are not made of pure wool
This tells are that AT MOST 100 sweaters at the store are NOT PURE WOOL sweaters.

Two contradicting statements.

I may be wrong.


I think so too.

It's saying in (1) that there are 320 Not Red and Not Wool and in statement (2) 100 are Not Wool. 320 is supposed to be a subset of the total sweaters that are not wool.
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Re: DS sets  [#permalink]

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New post 11 Apr 2011, 21:25
I too had spent 20 min on this question and was thinking what's wrong, I should have spotted the contradictory statements earlier ! Thanks a lot Ian.
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Re: DS sets  [#permalink]

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New post 11 Apr 2011, 22:19
Of the 800 sweaters in a certain store, 150 are red. How many of the red sweaters at the store are made of pure wool?

1) 320 of the sweaters at the store are neither red nor made of pool wool

2) 100 of the red sweaters at the store are not made of pure wool

800 = Only Red + Only Pure Wool + Both + neither

only red + both = 150

From (1)

Only Pure Wool = 800 - 150 - 320 = 800 - 470 = 330

But "Both" is stll not there.

So (1) is insufficient

(2) says

Only Red + both = 150

So both = 50

Answer - B
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Re: Of the 800 sweaters in a certain store, 150 are red. How  [#permalink]

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New post 23 Apr 2012, 19:48
Why do we assume no other material could be used to make the red sweaters? Why wouldn't 40 of the remaining sweaters be polyster instead of pure wool?

In that case wouldn't E be the appropriate answer?
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Re: Of the 800 sweaters in a certain store, 150 are red. How  [#permalink]

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New post 11 Jun 2013, 07:28
Bumping for review and further discussion*. Get a kudos point for an alternative solution!

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Re: Of the 800 sweaters in a certain store, 150 are red. How  [#permalink]

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New post 02 Oct 2013, 13:37
What if it is made out of another material other than wool?
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Re: Of the 800 sweaters in a certain store, 150 are red. How  [#permalink]

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Re: Of the 800 sweaters in a certain store, 150 are red. How  [#permalink]

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New post 22 Dec 2015, 04:12
I was thinking of C or E till I read meaning into (2). (2) is talking of RED sweaters!
and A hundred of the Red sweaters are made of whatever other than pure wool. I.e. whatever that isn't pure wool. that means the rest are reds made of pure wools.
This question is really sub 600.
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Re: Of the 800 sweaters in a certain store, 150 are red. How  [#permalink]

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New post 20 Mar 2017, 22:27
Bunuel wrote:
ralmasri713 wrote:
What if it is made out of another material other than wool?


Sweaters made of some other materials fall into the category of "No Wool" (2nd row in the matrix given) and thus taken into consideration.

Does this make sense?


I see what you're saying- very silly mistake I made in my head- that's the point- how many are not made out of pure wool? The complement of that number is the amount of red sweaters made out of pure wool.
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Re: Of the 800 sweaters in a certain store, 150 are red. How  [#permalink]

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New post 20 Mar 2017, 22:33
IMO B ; you cant make out the answer with only 1st option as you can't find how many sweaters are of red and not wool. To get the value from the mentioned red sweaters. 2nd option right on the mark . answer B is enough . @bunel did a great job in explaining.
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Re: Of the 800 sweaters in a certain store, 150 are red. How  [#permalink]

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New post 24 Mar 2018, 07:35
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Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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