Vennz

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Vennz

by MBA.Aspirant » Tue Jun 21, 2011 4:02 pm
1. In a graduating class of 236 students, 142 took algebra and 121 took chemistry. What is the
greatest number of students that could have taken both algebra and chemistry?

(A) 21 (B) 27 (C) 37 (D) 121 (E) 142

My answer is 27, some are saying it's 121. What's your take?
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by winniethepooh » Tue Jun 21, 2011 4:38 pm
Should not exceed 27, acc to me!

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by Jim@Knewton » Tue Jun 21, 2011 6:35 pm
This is a somewhat obscure question and needs a supporting assumption for either answer ( 27 or 121)

Option 1: All 236 students are represented in "142 took algebra and 121 took chemistry"

=> Total = Math + Chem - Both

=> Both = 142+121-236 = 27

Option 2: NOT all 236 students are represented in "142 took algebra and 121 took chemistry" => there could be other students with Arts / Bio to make the total of 236.

=> Total = Math + Chem -Both + Other (Including other combination pairs etc;)

=> Maximum for Math and Chem together = Minimum of (Math, Chem) = 121

In such cases, it is good to think strategically and it is a bit unlikely (though possible) that the question-setter had option 2 in mind. Reason: Option 2 requires us to assume that the question does not provide complete information for the total value of 236 ( => it does not matter if it is 236 or any other greater value such as 400 or 500, this would be a little unusual for the GMAT). Hence option 1 may be a better choice: 27
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by navami » Wed Jun 22, 2011 4:56 am
Lets say 121 students opted for both Chem and A course.
In this case total number of students = 142(in 142 121students are enrolled for both the course) only where as in t he question the number of students = 236.
This time no looking back!!!
Navami