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A set has maximum number 4d above the mean and a minimum

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Director
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A set has maximum number 4d above the mean and a minimum [#permalink] New post 22 Jan 2011, 05:48
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A set has maximum number 4d above the mean and a minimum number 3d above the mean, where d (standard deviation) = 6. What is the range of this set?

A. 6
B. 18
C. 24
D. 42
E. 84

I just made a simple subtraction 4d -3d to arrive at d(6). Is this correct? Otherwise...
I wasn't sure because above and below the mean will be referring to the spread...
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Re: Range of a set [#permalink] New post 22 Jan 2011, 08:07
I would say its 42 and the wording is wrong. Max and min cannot be both above the mean...
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Re: Range of a set [#permalink] New post 22 Jan 2011, 09:26
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gmatbull wrote:
A set has maximum number 4d above the mean and a minimum number 3d above the mean,
where d (standard deviation) = 6. What is the range of this set?

A:6 B:18 C:24 D:42 E84
I just made a simple subtraction 4d -3d to arrive at d(6). Is this correct? Otherwise...
I wasn't sure because above and below the mean will be referring to the spread...


Yes, it should be that "a minimum number is 3d BELOW the mean".

Now, the range of a set is the difference between the largest and smallest elements of a set. So the range of our set is (mean+4d)-(mean-3d)=7d=42.

Answer: D.
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Re: Range of a set [#permalink] New post 22 Jan 2011, 10:26
yes, it's "3d below the mean" since that's a minimum. Thanks for the explanations.
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Re: Range of a set   [#permalink] 22 Jan 2011, 10:26
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A set has maximum number 4d above the mean and a minimum

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