Is M < 0

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Is M < 0

by anuptvm » Fri Dec 24, 2010 5:18 pm
Is M < 0 ?

1. - M = | -M|

2. M^2 =9

According to me Stmt 1 is sufficient

when M = 1; - (1) = |-1| = 1
when M = -1; -(-1) = |1| = 1
when M = 0 ; 0 = 0

So for all values of M; M >= 0 which is sufficient

The OA is C. Could someone explain
Source: — Data Sufficiency |

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by anshumishra » Fri Dec 24, 2010 5:24 pm
anuptvm wrote:Is M < 0 ?

1. - M = | -M|

2. M^2 =9

According to me Stmt 1 is sufficient

when M = 1; - (1) = |-1| = 1
when M = -1; -(-1) = |1| = 1
when M = 0 ; 0 = 0

So for all values of M; M >= 0 which is sufficient

The OA is C. Could someone explain
You made mistake here :
when M = 1; - (1) = |-1| = 1
Thanks
Anshu

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by Rahul@gurome » Fri Dec 24, 2010 6:17 pm
anuptvm wrote:Is M < 0 ?

1. - M = | -M|

2. M^2 =9

According to me Stmt 1 is sufficient

when M = 1; - (1) = |-1| = 1
when M = -1; -(-1) = |1| = 1
when M = 0 ; 0 = 0

So for all values of M; M >= 0 which is sufficient

The OA is C. Could someone explain

modulus is always zero or positive.
Consider first (1) alone.
It means -m => 0.
Or m <= 0.
So m is either 0 or less than 0.
Hence (1) alone is not sufficient.
Next consider (2) alone.
It means m = -3 or 3.
Again not sufficient.
On combining (1) and (2) m = -3 is the only value satisfying both the conditions and it is less than 0.
So both statements together are sufficient.
The correct answer is (C).
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