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If S is a set of four numbers w,x,y and z, is the range of [#permalink]
28 Jul 2009, 17:52
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If S is a set of four numbers w,x,y and z, is the range of the numbers in S greater than 2?
1 w-z > 2 2 z is the least number in S.
My approach was, since range is the difference between maximum and minimum numbers we need to check whether the range of S can be computed.
Statement 1. w-z > 2, however we don't know that w is the max and and z is the minimum. So NOT Sufficient
Statement 2. NOT Sufficient
Combining both since z is the least number so we can assume either w is the maximum number or w is only greater than z and smaller than x and y. Thus, IMO both together are sufficient and hence, answer should be C.
However, the OA is A.
Can someone explain where I am making a mistake. _________________
1. w-z>2 So irrespective of the other numbers the difference between w and z is greater than 2. Even if w and z are neither max nor min, as diff is GT 2 so the range should also be greater than 2. So 1 is sufficient. 2. Z is least number. But we do not have info abt other variables and their values in the set S.
for 1), you could also just move z over to the right to get w>2 +z. Regardless of whether w and/or z are pos/neg w still looks to be 2 more than z. Moving z should be safe since we are not dividing/multiplying a potentially negative number. _________________