Gmat prep

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Gmat prep

by sandranjeim » Sun Apr 18, 2010 11:48 am
How many of the 42 people in a group are employed students?

1) 29 of the 42 people are employed

2) 24 of the 42 people are students



why isn't C the answer solved through a ven diagram????

Thank You
E
Source: — Data Sufficiency |

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by kevincanspain » Sun Apr 18, 2010 11:52 am
Some people may be unemployed non-students
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by akhpad » Sun Apr 18, 2010 7:16 pm
This Q is not related to ven diagram

Please see the solution in image

Image

We can't find employed students even after combing statement 1 and 2

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by Testluv » Sun Apr 18, 2010 8:15 pm
sandranjeim wrote:How many of the 42 people in a group are employed students?

1) 29 of the 42 people are employed

2) 24 of the 42 people are students



why isn't C the answer solved through a ven diagram????

Thank You
E
You can use a venn diagram but you would have to draw a box around the two overlapping circes. In this box, the space outside of the two circles would represent people who are neither employed nor students. (As Kevin points out, you have assumed away this subset).

As akhp77 shows us, you can also set up a matrix chart.

You can also use the counting formula for two overlapping sets:

Total # = (# in group 1) + (# in group 2) - (# in both groups) + (# in neither group)

(The reason we subtract the number in both groups is that the objects in both groups have been counted twice--once in he count of objects in group 1, an again in the count of objects in group 2. We have to add in the number of obects in neither group because they haven't been counted at all).

This question asks us for the number of people in BOTH groups (employed and students). The stem provides us with the total number of objects while each statement provides us with the number in each group. So, in the formula we can plug in three values but we still have two unknowns (the number in both and the number in neither).
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