Bunuel wrote:

If ab ≠ 0, in what quadrant of the coordinate system below does point (a, b) lie?

(1) (b, a) lies in quadrant IV.

(2) (a, -b) lies in quadrant III.

Target question: In what quadrant of the coordinate system below does point (a, b) lie? Statement 1: (b, a) lies in quadrant IV. In Quadrant IV, the x-coordinate is

POSITIVE, and the y-coordinate is

NEGATIVESo, if (b, a) lies in quadrant IV, then b is

POSITIVE, and the a is

NEGATIVEIf a (the x-coordinate of (a,b)) is

NEGATIVE and b (the y-coordinate of (a,b)) is

POSITIVE, then (

a,

b), must lie in Quadrant II

So, the answer to the target question is

(a, b) lies in Quadrant IISince we can answer the

target question with certainty, statement 1 is SUFFICIENT

Statement 2: (a, -b) lies in quadrant III.In Quadrant III, the x-coordinate is

NEGATIVE, and the y-coordinate is

NEGATIVESo, if (a, -b) lies in quadrant III, then a is

NEGATIVE, and the -b is

NEGATIVEIf -b is

NEGATIVE, then b is

POSITIVEIf a (the x-coordinate of (a,b)) is

NEGATIVE and b (the y-coordinate of (a,b)) is

POSITIVE, then (

a,

b), must lie in Quadrant II

So, the answer to the target question is

(a, b) lies in Quadrant IISince we can answer the

target question with certainty, statement 2 is SUFFICIENT

Answer: D

Cheers,

Brent

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