GMAT Prep 1 PS 23

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GMAT Prep 1 PS 23

by starxx68 » Sun Dec 30, 2007 6:45 pm
Three boxes of supplies have an average weight of 7kg and a median weight of 9kg. What is the maximum possible weight, in kg, of the lightest box?

A) 1
B) 2
C) 3
D) 4
E) 5

I keep getting B, and the OA is C. This is my reasoning:

If median is 9, then heaviest box must be greater than 9.

(x+9+10)/3 = 7
x +19 = 21
x = 2
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by Tud » Sun Dec 30, 2007 6:58 pm
(x+9+10)/3 = 7

If you are using 10 in the above equation to represent the heaviest box then that's the error. The heaviest box can be 9 and you will still have a medium of 9 if the boxes weigh 3, 9, 9.