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ricaototti
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 Posted: Thu Sep 04, 2008 9:33 pm Post subject: stats |
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If set S = {7, y, 12, 8, x, 9}, is x + y less than 18?
(1) The range of set S is less than 9.
(2) The average of x and y is less than the average of set S.
OA b
But I dont get the reasoning. I would like to have a step by step explanation of why B is correct.
What I did for B: I just plugged in a few numbers.That is what I usually do when I dont have a quick nice approach to tackle the question. Should I change this strategy? It doesnt always work out all right...
How many questions on Stats in the real GMAT? By stats I mean what includes mean, range, std, median....
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parallel_chase
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| Posted: Fri Sep 05, 2008 2:36 am Post subject: Re: stats |
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| ricaototti wrote: | If set S = {7, y, 12, 8, x, 9}, is x + y less than 18?
(1) The range of set S is less than 9.
(2) The average of x and y is less than the average of set S.
OA b
But I dont get the reasoning. I would like to have a step by step explanation of why B is correct.
What I did for B: I just plugged in a few numbers.That is what I usually do when I dont have a quick nice approach to tackle the question. Should I change this strategy? It doesnt always work out all right...
How many questions on Stats in the real GMAT? By stats I mean what includes mean, range, std, median....
THANKS |
Statement I
range of the set is less than 9, x could be anything and y could be anything.
x+y can be less than 18, x+y can be more than 18.
Insufficient.
Statement II
(x+y)/2 < (36+x+y)/6
(x+y)/2 < 6 + (x+y)/6
x+y < 12 + (x+y)/3
If you insert values for x and y, you will notice that x+y will always be less than 18 to satisfy the above equation.
Answer is no.
Hence Sufficient.
Answer is B.
You can see anywhere between 2-3 questions on stats, but it could be more or it could be less on the actual GMAT.
Hope this helps. |
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mayur00
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| Posted: Fri Sep 05, 2008 9:40 am Post subject: |
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I think ricaototti's solutions is correct.
However, you can further simplify
(x+y)/2 < (36+x+y)/6
to give x+y<18 |
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