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[gmat_action]

As x increases from 165 to 166, which of the statement/s must increase ?

1) 2x-5

2) 1-1/x

3) 1/(xsquare - x )

[GMATGuruNY]

As x increases from 165 to 166, which of the following must increase ?

I) 2x-5

II) 1-1/x

III) 1/(x^2 - x)

A. I only
B. II only
C. I and II
D. I and III
E. II and III

The numbers given in the question are irrelevant.
Answer the following:

As x increases from 2 to 3, which of the following must increase?

I. 2x-5
When x=2, 2x-5 = (2*2)-5 = -1.
When x=3, 2x-5= (2*3)-5 = 1.
Since the value of 2x-5 increases, eliminate any answer that does not include I.
Eliminate B and E.

II. 1-(1/x)
When x=2, 1-(1/x) = 1-(1/2) = 1/2.
When x=3, 1-(1/x)= 1-(1/3) = 2/3.
Since the value of 1-(1/x) increases, eliminate any answer that does not include II.
Eliminate A and D.

The correct answer is C.