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 Post subject: The sum of integers in list S is the same as the sum of the
 Post Posted: Tue Oct 13, 2009 6:42 pm 
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Students


Posts: 11
Is there a quick/efficient way of doing this DS problem. The way i do it i.e. by putting in numbers and creating sets, is long and there is a chance of error if not done correctly. Can anyone please share there methods for this question. Greatly appreciated : )

The sum of integers in list S is the same as the sum of the integers in T. Does S contain more integers than T?
1) The mean of integers in S is less than the mean of integers in T
2) The median of integers S is greater than the median of integers T

ANSWER is: A


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 Post subject: Re: The sum of integers in list S is the same as the sum of the
 Post Posted: Wed Oct 14, 2009 11:39 am 
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Students


Posts: 68
Let Set S have s integers and Set T have t integers.
lets write SUM S as sum of all integers in Set S and SUM T as Sum of integers in Set T.

We are give SUM S = SUM T

Question is asking whether s>t .

Hope its clear till this point.

Statement 1 says The mean of integers in S is less than the mean of integers in T

Which means

SUM S / s < SUM T / t (hope the ineuality is clear)
since SUM S = SUM T

1/s < 1/t (remember s and t are positive integers because they represent number of integers in a Set)

Since 1/s < 1/t implies s>t.
St.1 is SUFFICIENT

Statement 2 The median of integers S is greater than the median of integers T

Now here you need to plug in,
S could be 1,2,3, Sum = 6, Median = 2

T could be 1,1,4 , Sum = 6, Median = 1
Or T could be 3,3 Sum = 6, Median = 3

As we can see There could be multiple scenarios where two sets can have same sum, Median can be equal or different and still they can have different number of integers.

So INSUFFICIENT

Answer A


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 Post subject: Re: The sum of integers in list S is the same as the sum of the
 Post Posted: Wed Oct 14, 2009 6:18 pm 
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Students


Posts: 11
Awesome : ) this is a much efficient way of doing it. Thanks alot man i really appreciate all your help.


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 Post subject: Re: The sum of integers in list S is the same as the sum of the
 Post Posted: Sat Oct 24, 2009 7:50 am 
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ManhattanGMAT Staff


Posts: 7146
does this problem state that the integers must be positive (or, at the least, non-negative)?

if not, then the actual answer is (e).

proof:
post24047.html#p24047


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