Distances

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Distances

by gmat009 » Wed Nov 12, 2008 9:02 am
OA is C but IMO B is sufficient.
From B I am getting r+s=0
r=-s, so B is sufficient.
Why answer is C. Can someone plz. explain why do we need A
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Re: Distances

by logitech » Wed Nov 12, 2008 9:23 am
gmat009 wrote:OA is C but IMO B is sufficient.
From B I am getting r+s=0
r=-s, so B is sufficient.
Why answer is C. Can someone plz. explain why do we need A
Gmat009,

Lets do this exercise:

Solve this question for

S=0

and

S<0

let's see what you get. Feel free to use numbers.
LGTCH
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"DON'T LET ANYONE STEAL YOUR DREAM!"

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Re: Distances

by gmat009 » Wed Nov 12, 2008 9:49 am
logitech wrote:
gmat009 wrote:OA is C but IMO B is sufficient.
From B I am getting r+s=0
r=-s, so B is sufficient.
Why answer is C. Can someone plz. explain why do we need A
Gmat009,

Lets do this exercise:

Solve this question for

S=0

and

S<0

let's see what you get. Feel free to use numbers.
We cannot take s=0.
In option B he says that "Distance between t and -s".
If s is 0 the 2nd equation cannot say -s becoz 0 is neither positive nor negative.
Let me know if I am thinking wrong or missing something

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Re: Distances

by logitech » Wed Nov 12, 2008 9:56 am
gmat009 wrote:
Let me know if I am thinking wrong or missing something
You are good. Try the next one:

S<0
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Re: Distances

by gmat009 » Wed Nov 12, 2008 10:45 am
logitech wrote:
gmat009 wrote:
Let me know if I am thinking wrong or missing something
You are good. Try the next one:

S<0
If s<0 , then r=-(-s)
r=s and s=-s
Therefore this is sufficient becoz if s=-3, then r=3, if s=-4, then r=4
So r and s have opposite signs and 0 is halfway between r and s

Now take s>0
This is also sufficient becoz if s=3, then r=-3, if s=4, then r=-4
So r and s have opposite signs and 0 is halfway between r and s

Regardless s is positive or negative, r is opposite to s and 0 lies in midway

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Re: Distances

by logitech » Wed Nov 12, 2008 12:33 pm
gmat009 wrote:
logitech wrote:
gmat009 wrote:
Let me know if I am thinking wrong or missing something
You are good. Try the next one:

S<0
If s<0 , then r=-(-s)
r=s and s=-s
Therefore this is sufficient becoz if s=-3, then r=3, if s=-4, then r=4
So r and s have opposite signs and 0 is halfway between r and s

Now take s>0
This is also sufficient becoz if s=3, then r=-3, if s=4, then r=-4
So r and s have opposite signs and 0 is halfway between r and s

Regardless s is positive or negative, r is opposite to s and 0 lies in midway


R----------S---------T-------------O---------------- -S

-S.................0-------R--------S----------T


-S------R----0----------S------------T

R----------S---------0---------------t--------S

R----------S---------0---------S-------t-

Think again:

TR is equal to T-S ?
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"