Hi
This question comes from the 08-09 edition of Kaplan GMAT 800 (DS-Straight Math no. 16, p364).
If a, b and c are distinct nonzero numbers, is
((a+b)^2 * (b-c))/((a-b)^3 * (b-c)^3) greater or equal to zero?
1) a>b
2) b>c
Solution given:
Find out if the expression is non-negative. Simplify expression to (a+b)^2 / ((a-b)^3 * (b-c)^2). The signs of the squared terms must be positive whilst the sign of the cubed term is unknown. But if the latter is not negative, expression is not negative ie. if a>b. Statement 1 tells you, so answer is (A).
However statement 1 could be true and cubed term could still be negative eg. a=-2, b=-3. So I believe the correct answer is (E)!
Agreed?
Cheers
This question comes from the 08-09 edition of Kaplan GMAT 800 (DS-Straight Math no. 16, p364).
If a, b and c are distinct nonzero numbers, is
((a+b)^2 * (b-c))/((a-b)^3 * (b-c)^3) greater or equal to zero?
1) a>b
2) b>c
Solution given:
Find out if the expression is non-negative. Simplify expression to (a+b)^2 / ((a-b)^3 * (b-c)^2). The signs of the squared terms must be positive whilst the sign of the cubed term is unknown. But if the latter is not negative, expression is not negative ie. if a>b. Statement 1 tells you, so answer is (A).
However statement 1 could be true and cubed term could still be negative eg. a=-2, b=-3. So I believe the correct answer is (E)!
Agreed?
Cheers
