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# Of the 70 children who visited a certain doctor last week,

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Manager
Joined: 20 Nov 2009
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Of the 70 children who visited a certain doctor last week,  [#permalink]

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17 Aug 2010, 09:57
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Difficulty:

25% (medium)

Question Stats:

77% (01:11) correct 23% (01:05) wrong based on 117 sessions

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Of the 70 children who visited a certain doctor last week, how many had neither a cold nor a cough?

(1) 40 of the 70 children had a cold but not a cough.

(2) 20 of the 70 children had both a cold and a cough.

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17 Aug 2010, 10:23
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aiming4mba wrote:
Of the 70 children who visited a certain doctor last week, how many had neither a cold nor a cough?

(1) 40 of the 70 children had a cold but not a cough.

(2) 20 of the 70 children had both a cold and a cough.

All={Children with a cough ONLY}+{Children with a cold ONLY}+{Children with a cough AND a cold}+{Children with neither a cold nor a cough} --> 70={Children with a cough ONLY}+{Children with a cold ONLY}+{Children with a cough AND a cold}+{Children with neither a cold nor a cough}

(1) 40 of the 70 children had a cold but not a cough --> so {Children with a cold ONLY}=40. Not sufficient.

(2) 20 of the 70 children had both a cold and a cough --> so {Children with a cough AND a cold}=20. Not sufficient.

(1)+(2) 70={Children with a cough ONLY}+40+20+{Children with neither a cold nor a cough} --> 10={Children with a cough ONLY}+{Children with neither a cold nor a cough}, still 2 unknowns. Not sufficient.

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17 Aug 2010, 11:17
great explanation bunuel. thanks!
Manager
Joined: 20 Apr 2010
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WE 1: 4.6 years Exp IT prof

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17 Aug 2010, 11:44

To calculate the result one should the nos of Children who had Cough but not cold.
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17 Aug 2010, 20:38
Bunuel, you're the best!
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But there’s something in me that just keeps going on. I think it has something to do with tomorrow, that there is always one, and that everything can change when it comes.
http://aimingformba.blogspot.com
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28 Aug 2010, 02:37
Bunuel is the reason for the success of this forum. Thanks a lot to Bunuel!!
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Re: Of the 70 children who visited a certain doctor last week,  [#permalink]

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22 Jan 2018, 04:58
Hello from the GMAT Club BumpBot!

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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Re: Of the 70 children who visited a certain doctor last week,   [#permalink] 22 Jan 2018, 04:58
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