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HELP - - -mean,range DS

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HELP - - -mean,range DS

by tdadic84 » Wed May 27, 2009 2:47 pm
from gmatclub

Is the smallest number of Set X bigger than the smallest number of Set Y?

1) The range of Set X is bigger then the range of Set Y

2) The mean of set X is bigger then the mean of Set Y

please solve with detail..
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Source: — Data Sufficiency |
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by cramya » Wed May 27, 2009 7:57 pm
I would go with E

1) The range of Set X is bigger then the range of Set Y

X-> 1 1BILLION
Y-> 1 2

NO

X-> 2 1BILLION
Y-> 1 2

YES

INSUFF

2) The mean of set X is bigger then the mean of Set Y

X: 1 5 9

Y: 1 2 3

NO

X: 2 5 8
Y: 1 2 3

YES

INSUFF

TOGETHER:


X: 1 5 9

Y: 1 2 3


X: 2 5 8
Y: 1 2 3

INSUFF
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by humans » Wed May 27, 2009 8:03 pm
1) The range of Set X is bigger then the range of Set Y.

This only tells us that the difference between the largest and smallest number in set X is greater than the difference between the largest and smallest number in set Y. Insufficient.

2) The mean of set X is bigger then the mean of Set Y

This only tells us the concentration of larger numbers is more in X than in Y. Insufficient.

Taking together only tells us that set X has more large numbers and it range is bigger than set Y, but this doesn't answer the questions.

Hence E is the answer.
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by cramya » Wed May 27, 2009 8:07 pm
You may already know this but the range = Highest - Lowest (in the list)

Note:

For any set of consecutive integers or ArithmeticProgression(common difference between successive elements)

Mean= Median = average of first and last

In some DS probs knowing the fact above may prove helpful!

Regards,
CR
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by abhinav85 » Thu May 28, 2009 9:38 am
IMO E.
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