Gmat Prep - Standard deviation and mean

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mehravikas wrote:Clueless on this one.
Please search before posting.. this has been answered several times...

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Re: Gmat Prep - Standard deviation and mean

by mim3 » Mon Aug 25, 2008 7:57 am
[quote="mehravikas"]Clueless on this one.[/quote]

We know that the difference in the two scores is 40 and there are 5 SD's between them. Divide to find the amount of 1 SD: 40/5= 8. Because it's known that 58 is 2 SD's below the mean add 16 to 58 to get the answer, 74.

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mim3 wrote:
mehravikas wrote:Clueless on this one.
We know that the difference in the two scores is 40 and there are 5 SD's between them. Divide to find the amount of 1 SD: 40/5= 8. Because it's known that 58 is 2 SD's below the mean add 16 to 58 to get the answer, 74.
ur way is so cool

i set SD as variable X and two condition given in the question, can thus be derived into 2 equations
M-2X=58
M+3x=98
X = 8, therefore, M-Mean=74