If a and b are positive, is (a^-1 + b^-1)^-1 less than (a^-1b^-1)^-1?
(1) a = 2b
(2) a + b > 1
Shouldn't the answer be E?
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Note the following:Abhijit K wrote:If a and b are positive, is (a^-1 + b^-1)^-1 less than (a^-1b^-1)^-1?
(1) a = 2b
(2) a + b > 1
x¯¹ = 1/x.
Question:
Is 1 / (1/a + 1/b) < 1 / (1/ab)?
Since a and b are positive, the question stem can be rephrased as follows:
1 / [(a+b)/ab] < ab
ab/(a+b) < ab
1/(a+b) < 1
1 < a+b.
Question stem, rephrased:
Is a+b > 1?
Statement 1: a=2b
If b=1 and a=2, then a+b > 1.
If b=0.1 and a=0.2, then a+b < 1.
INSUFFICIENT.
Statement 2: a+b > 1
SUFFICIENT.
The correct answer is B.
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