is it E ?mridula wrote:If ax + b = 0, is x > 0?
a. a + b > 0
b. a - b > 0
Please provide explanation. OA to follow.
from stmt1 or 2 and even combining them a and b can be -ve or +ve so can't determine
GMAT Prep DS question.
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linkinpark
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from stmt1 or 2 and even combining them a and b can be -ve or +ve so can't determine
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onedayi'll
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ax+b=0
x = -b/a
For x>0 either (a<0 ,b>0) or (a>0,b<0)
Implies that a and b should have opposite signs
1) a + b >0, tells us nothing a and b could both be greater or one can be positive and other can be negative.
INSUFF
2) a - b >0, tells us nothing a and b could both be greater or one can be positive and other negative.
INSUFF
combining both stmts, we still dont know, if a and b have opposite signs for sure.
Therefore E.
x = -b/a
For x>0 either (a<0 ,b>0) or (a>0,b<0)
Implies that a and b should have opposite signs
1) a + b >0, tells us nothing a and b could both be greater or one can be positive and other can be negative.
INSUFF
2) a - b >0, tells us nothing a and b could both be greater or one can be positive and other negative.
INSUFF
combining both stmts, we still dont know, if a and b have opposite signs for sure.
Therefore E.
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GMAT...TED
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Lets nail this one...mridula wrote:If ax + b = 0, is x > 0?
a. a + b > 0
b. a - b > 0
Please provide explanation. OA to follow.
Give: ax+b=0. This, if simplified is x=-b/a
And, we need to find out if X>0... Which means we need to understand the polarity of a & b
Choice 1: a+b>0
Possible only if both are positive or one is positive(the bigger one)... which does on answer the question
Choice 2: a-b>0
Possible only if both are positive and a>b or b is negative or both are negative... Many possibilities... So unclear
Jointly...
Statement 1 indicates that either both are positive or one is positive
Statement 2 also indicates that either both are positive or b is negative... both can not be negative for statement 1 to be true...
No definitive answer is possible... I Choose E... OA Please....
My doubt is... if the second equation is a*b or a-b? The main screen looks like a*b and quote mode shows is to be a-b...
if it is a*b, then the answer will change...and in that case
Choice 2: a*b>0
Both could be positive or both could be negative...
Jointly
Equation 1 tells me that either both are positive or atleast one is positive...
Equation 2 indicates that either both are positive or both negative... but or 1 to be true... both can not be negative... So both are positive...
A definitive answer ... I choose C... OA with clarification please...
