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by pemdas » Mon Dec 05, 2011 12:48 pm
Set Z contains positive numbers 36, 47, a and b. Find the value of b, if a<c<b, and c is a median equal to fifteen times the interquartile range of the set Z.

A. 37
B. 37.5
C. 38
D. 39
E. 40

ans: C
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Last edited by pemdas on Mon Dec 05, 2011 2:39 pm, edited 2 times in total.
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by VivianKerr » Mon Dec 05, 2011 1:38 pm
pemdas, I love your name. :)

"interquartile range" is pretty much outside the GMAT scope (in fact, I don't think I've EVER seen it before on a GMAT question), but it refers to the "middle fifty." That is, the data between 25-75% of the range. Looking at this, since we have more than three unknowns, I don't think it's possible to solve.
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by pemdas » Mon Dec 05, 2011 1:54 pm
you need a bit thinking to see that the largest known number is greater than any number in the answer choices A-E and the unknown number b can be immediately placed on its right order, since b>c and c is the interquartile range, as you correctly noted (not tested on GMAT? :roll: , why would the Math conventions include this then).

A solution is quite easy ...
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