smartass666 wrote:
Given that the mean of Set A is 10, what is the range of two standard deviations above and below the mean?
(1) One standard deviation above and below the mean ranges from 7 to 13.
(2) The median of set A is 11.
Actually its a simple question if you understand what exactly it is trying to tell you??
Mean(m)=10 (Given) ;
Asked=Range of two std. dev. above & below mean ,i.e, (m-2d) & (m+2d) ??
From, (1) its clear (m-d) & (m+d) are 7 & 10 respectively ; Therefore, (m-d)=7 =>d=10-7=3 =>m-2d & m+2d are (10-2x3) & (10+2x3) OR 4 & 16 respectively;
Hence, (1) is SUFFICIENT ;
From, (2) we get no clue about std. dev. as it talks about median only ;
Hence, (2) is INSUFFICIENT ;
Thus, answer is option A ; All the best !!
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GMAT date:- 21-12-2019
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