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11 Aug 2017, 03:43
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E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
5%
(low)
Question Stats:
87% (00:55) correct
13%
(01:05)
wrong
based on 493
sessions
History
Date
Time
Result
Not Attempted Yet
If b is positive, is ab positive?
(1) \(a^2b>0\)
(2) \(a^2+b=13\)
(1) \(a^2b>0\)
(2) \(a^2+b=13\)
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11 Aug 2017, 04:14
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For ab>0 => a and b must be of the same sign.
So by giving us b>0 the question is really asking us if a>0 or not.
So the question can be transformed into -->
If b>0 then Is a>0 .
Lets begin.
Statement 1-->
a^2 * b > 0
This just tells us that a≠0
a can be positive or negative a^2*b will always be positive.
Hence not sufficient.
Statment 2->
Lets use two examples =>
(0,13)
(1,12)
Hence not sufficient.
Combining the two statements =>
(x,y) => (-1,12) or (1,12) are two easy test cases to take.
Hence not sufficient.
Hence E.
So by giving us b>0 the question is really asking us if a>0 or not.
So the question can be transformed into -->
If b>0 then Is a>0 .
Lets begin.
Statement 1-->
a^2 * b > 0
This just tells us that a≠0
a can be positive or negative a^2*b will always be positive.
Hence not sufficient.
Statment 2->
Lets use two examples =>
(0,13)
(1,12)
Hence not sufficient.
Combining the two statements =>
(x,y) => (-1,12) or (1,12) are two easy test cases to take.
Hence not sufficient.
Hence E.
11 Aug 2017, 04:27
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I would go for E as well.
1) A^2b > 0 A can be any value and so can B (positive)
2) A^2+B =13
A^2 can be 12
B can be 1
or A^2 (-1^2) can 1
B can be 12
both 1 and 2 - No difference.
I hope its correct
1) A^2b > 0 A can be any value and so can B (positive)
2) A^2+B =13
A^2 can be 12
B can be 1
or A^2 (-1^2) can 1
B can be 12
both 1 and 2 - No difference.
I hope its correct
11 Aug 2017, 05:42
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Bookmarks
If b is positive, is ab positive?
1. \(a^2b>0\)
Since we are given b is positive,
if a is either positive or negative, the expression \(a^2b>0\) holds true.
Case 1: a=-3, b=2 Here, ab is negative
Case 2: a=3, b=2 Here, ab is positive(Insufficient)
2. \(a^2+b=13\)
Since we are given b is positive,
if a is either positive or negative, the expression \(a^2+b=13\) holds true.
Case 1: a=-3, b=5 Here, ab is negative
Case 2: a=3, b=5 Here, ab is positive(Insufficient)
Even combining both the statements, we will be left with two options
in the first one - both a and b are positive
in the second one - a is negative and b is positive. (Insufficient)(Option E)
1. \(a^2b>0\)
Since we are given b is positive,
if a is either positive or negative, the expression \(a^2b>0\) holds true.
Case 1: a=-3, b=2 Here, ab is negative
Case 2: a=3, b=2 Here, ab is positive(Insufficient)
2. \(a^2+b=13\)
Since we are given b is positive,
if a is either positive or negative, the expression \(a^2+b=13\) holds true.
Case 1: a=-3, b=5 Here, ab is negative
Case 2: a=3, b=5 Here, ab is positive(Insufficient)
Even combining both the statements, we will be left with two options
in the first one - both a and b are positive
in the second one - a is negative and b is positive. (Insufficient)(Option E)
