p (with slope m) and q (with slope n)

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p (with slope m) and q (with slope n)

by sanju09 » Thu Aug 26, 2010 8:44 pm
Are lines p (with slope m) and q (with slope n) perpendicular to each other?

1. m + 2 = n.
2. m + n = 0.


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by 4GMAT_Mumbai » Thu Aug 26, 2010 8:58 pm
Hi,

It is a nice q ...

Stmt 1:

m + 2 = n

m could be 3 and n will be 5. Not perpendicular.
m could be -1 and n will be 1. Perpendicular.

Hence, insuff.

Stmt 2:

m could be 3 and n will be -3. Not perpendicular.
m could be -1 and n will be 1. Perpendicular.

Hence, insuff.

Combine:

m - n = -2
m + n = 0

2m = -2 implies m = -1 and n = 1. Perpendicular

Suff. Hence, C

Hope this helps. Thanks.
Naveenan Ramachandran
4GMAT, Dadar(W) & Ghatkopar(W), Mumbai

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by sanju09 » Thu Aug 26, 2010 9:08 pm
C is correct, and the work is correct too.
Naveenan Ramachandran

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