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When 1,000 children were inoculated with a certain vaccine,

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When 1,000 children were inoculated with a certain vaccine, [#permalink]

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New post Updated on: 11 May 2014, 06:25
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When 1,000 children were inoculated with a certain vaccine, some developed inflammation at the site of the inoculation and some developed fever. How many of the children developed inflammation but not fever ?

(1) 880 children developed neither inflammation nor fever
(2) 20 children developed fever

Originally posted by elgo on 25 Oct 2007, 08:42.
Last edited by Bunuel on 11 May 2014, 06:25, edited 1 time in total.
Renamed the topic, edited the question and added the OA.
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When 1,000 children were inoculated with a certain vaccine, [#permalink]

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New post 11 May 2014, 06:38
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dhirajx wrote:
It seems there is no detail about children developing inflammation and fever. It is safe to assume there is no A∩B unless it is clearly mentioned in the question?


No, you cannot assume that. It's vise-versa, if there is no overlap, then you'd be told that in one way or another.

When 1,000 children were inoculated with a certain vaccine, some developed inflammation at the site of the inoculation and some developed fever. How many of the children developed inflammation but not fever ?

(1) 880 children developed neither inflammation nor fever
(2) 20 children developed fever

Image

Answer: C.



Hope this helps.

Attachment:
Untitled.png
Untitled.png [ 16.6 KiB | Viewed 12572 times ]

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 [#permalink]

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New post 25 Oct 2007, 09:49
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Oh, now I see that I mistakenly understood the second st.! I read it as 20 children developed fever but not inflammation.

Ok, that's it! Two CATs per day is too much!

Thanks!
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Re: GMAT prep 1, Q26 (DS) [#permalink]

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New post 28 Oct 2007, 23:42
1
elgo wrote:
Obviously, smth is wrong with my brain, but I couldn't understand the OA...

When 1,000 children were inoculated with a certain vaccine, some developed inflammation at the site of the inoculation and some developed fever. How many of the children developed inflammation but not fever?

1. 880 children developed neither inflammation nor fever
2. 20 children developed fever


any thoughts?


The answer is C, combine the 2 statements and its sufficient

1000-880(neither)-20(fever) =100
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 [#permalink]

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New post 29 Oct 2007, 01:49
St1:
just tells us that #(inflmmation only) + #(fever only) + #(both fever and inflmmation) = 120. Insufficient.

St2:
Just tells us if #(fever and inflmmation) = x, then #(fever only) = 20-x. Insufficient.

St1 and St2:
#(inflmmation only) = I-x
#(inflmmation and fever) = x
#(fever only) = 20-x

So I-x + x + 20-x = 120
I-x = 100
#(inflmmation only) = 100

Sufficient.

Ans C

P.S: Solved using Venn Diagram.
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Re: When 1,000 children were inoculated with a certain vaccine [#permalink]

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New post 11 May 2014, 05:48
It seems there is no detail about children developing inflammation and fever. It is safe to assume there is no A∩B unless it is clearly mentioned in the question?
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Re: When 1,000 children were inoculated with a certain vaccine, [#permalink]

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New post 21 Oct 2016, 23:51
Hello,

I tried solving this question through Venn Diagram. Putting the attachment here. Could anyone please let me know where am I lacking?
Total Sample = 1000
Neither I nor Fever = 880
Remaining = 120 with either Fever or Inf. or both.
Fever = 20

So, only Inflammation or Inflammation and fever = 100

And hence, according to me, I can't find the answer for the question, hence Statements are insufficient. :roll:
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Re: When 1,000 children were inoculated with a certain vaccine, [#permalink]

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New post 04 Jan 2017, 08:34
Top Contributor
Bunuel wrote:
dhirajx wrote:
It seems there is no detail about children developing inflammation and fever. It is safe to assume there is no A∩B unless it is clearly mentioned in the question?


No, you cannot assume that. It's vise-versa, if there is no overlap, then you'd be told that in one way or another.

When 1,000 children were inoculated with a certain vaccine, some developed inflammation at the site of the inoculation and some developed fever. How many of the children developed inflammation but not fever ?

(1) 880 children developed neither inflammation nor fever
(2) 20 children developed fever

Attachment:
Untitled.png

Answer: C.

Theory on Overlapping Sets:
advanced-overlapping-sets-problems-144260.html
how-to-draw-a-venn-diagram-for-problems-98036.html

All DS Overlapping Sets Problems to practice: search.php?search_id=tag&tag_id=45
All PS Overlapping Sets Problems to practice: search.php?search_id=tag&tag_id=65


Hope this helps.


Bunnel - do you have a rule of thumb about when to use Venn Diagram and when to use matrix table?
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Re: When 1,000 children were inoculated with a certain vaccine, [#permalink]

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New post 04 Jan 2017, 10:29
dimitri92 wrote:
Bunuel wrote:
dhirajx wrote:
It seems there is no detail about children developing inflammation and fever. It is safe to assume there is no A∩B unless it is clearly mentioned in the question?


No, you cannot assume that. It's vise-versa, if there is no overlap, then you'd be told that in one way or another.

When 1,000 children were inoculated with a certain vaccine, some developed inflammation at the site of the inoculation and some developed fever. How many of the children developed inflammation but not fever ?

(1) 880 children developed neither inflammation nor fever
(2) 20 children developed fever

Attachment:
Untitled.png

Answer: C.

Theory on Overlapping Sets:
advanced-overlapping-sets-problems-144260.html
how-to-draw-a-venn-diagram-for-problems-98036.html

All DS Overlapping Sets Problems to practice: search.php?search_id=tag&tag_id=45
All PS Overlapping Sets Problems to practice: search.php?search_id=tag&tag_id=65


Hope this helps.


Bunnel - do you have a rule of thumb about when to use Venn Diagram and when to use matrix table?


For 2 groups I almost always use a matrix.
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Re: When 1,000 children were inoculated with a certain vaccine, [#permalink]

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New post 04 Jan 2017, 11:11
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Thanks for the quick response Bunnel.
May be I am doing something wrong here and not seeing the right logic. I will appreciate your help here:
I don't see two groups. I see one group of kids who can either get one ailment or another. How do we decide if the groups are two or one?
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Re: When 1,000 children were inoculated with a certain vaccine, [#permalink]

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New post 05 Jan 2017, 03:34
dimitri92 wrote:
Thanks for the quick response Bunnel.
May be I am doing something wrong here and not seeing the right logic. I will appreciate your help here:
I don't see two groups. I see one group of kids who can either get one ailment or another. How do we decide if the groups are two or one?


Please check the matrix below:
Image
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Re: When 1,000 children were inoculated with a certain vaccine, [#permalink]

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New post 21 Mar 2017, 23:29
[quote="elgo"]When 1,000 children were inoculated with a certain vaccine, some developed inflammation at the site of the inoculation and some developed fever. How many of the children developed inflammation but not fever ?

(1) 880 children developed neither inflammation nor fever
(2) 20 children developed fever[/quote

In order to solve this question we need to know the number of children who developed neither and the number of children who developed fever- it is important to note this is a binary group- based on the stimulus it is assumed that there is no group that developed inflammation and fever at the site of inoculation.

Statement (1) gives us only one piece of the equation. Insufficient

Statement (2) still leaves us with the variable of the number of children who developed neither inflammation nor fever. Insufficient.

Statement (1) and Statement (2) together allow us the calculate the number of children who developed inflammation- only because there is no overlap with these groups

Total= A + B - Neither ( in this scenario A cannot be A + C (overlap) because it is inferred from the problem, again, you either have developed inflammation or have developed a fever)
1000= A + 20- 880
120= A + 20
100= A
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Re: When 1,000 children were inoculated with a certain vaccine, [#permalink]

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New post 22 Mar 2017, 02:32
elgo wrote:
When 1,000 children were inoculated with a certain vaccine, some developed inflammation at the site of the inoculation and some developed fever. How many of the children developed inflammation but not fever ?

(1) 880 children developed neither inflammation nor fever
(2) 20 children developed fever

total = children(nothing) + children(fever only) +children (inflammation only) +children (both)
children(fever) = children(fever only) +children(both)

St1: 1000 = 880 + children(fever only) +children (inflammation only) +children (both). three variables. one equation.INSUFFICIENT
1000 = 880 +Children (fever) + Children (inflammation only)

St 2: 20 = children(fever only) +children(both)
therefore 1000 = children(nothing) + 20 +children (inflammation only)

St 1 & St 2: 1000 = 880 +20 +Children(inflammation only)

children (Inflammation only) = 100. ANSWER

Option C
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When 1,000 children were inoculated with a certain vaccine, [#permalink]

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New post 25 Nov 2017, 01:17
Bunuel wrote:
dhirajx wrote:
It seems there is no detail about children developing inflammation and fever. It is safe to assume there is no A∩B unless it is clearly mentioned in the question?


No, you cannot assume that. It's vise-versa, if there is no overlap, then you'd be told that in one way or another.

When 1,000 children were inoculated with a certain vaccine, some developed inflammation at the site of the inoculation and some developed fever. How many of the children developed inflammation but not fever ?

(1) 880 children developed neither inflammation nor fever
(2) 20 children developed fever

Image

Answer: C.



Hope this helps.

Hi Bunuel,

I have a question here.. Usually the formula for two groups is :

Total = Group A+ Group B+ Neither - Both

In this question, why are we missing out the case for Both?

On combining both the statements:

1000= 20(Fever)+X (for Inflammation) +880 (Neither) - Both(Suffering from both)

So we have two unknown variables X and Both..

Answer should E in that case..
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Re: When 1,000 children were inoculated with a certain vaccine, [#permalink]

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New post 25 Nov 2017, 01:22
Pratyaksh2791 wrote:
Bunuel wrote:
dhirajx wrote:
It seems there is no detail about children developing inflammation and fever. It is safe to assume there is no A∩B unless it is clearly mentioned in the question?


No, you cannot assume that. It's vise-versa, if there is no overlap, then you'd be told that in one way or another.

When 1,000 children were inoculated with a certain vaccine, some developed inflammation at the site of the inoculation and some developed fever. How many of the children developed inflammation but not fever ?

(1) 880 children developed neither inflammation nor fever
(2) 20 children developed fever

Image

Answer: C.



Hope this helps.

Hi Bunuel,

I have a question here.. Usually the formula for two groups is :

Total = Group A+ Group B+ Neither - Both

In this question, why are we missing out the case for Both?

On combining both the statements:

1000= 20(Fever)+X (for Inflammation) +880 (Neither) - Both(Suffering from both)

So we have two unknown variables X and Both..

Answer should E in that case..


If you re-read the solution you quote carefully, you'll see that we can solve this particular question without that formula and without knowing both.
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Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


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Re: When 1,000 children were inoculated with a certain vaccine,   [#permalink] 25 Nov 2017, 01:22
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