Is d negative?

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okigbo
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Topic: Is d negative?
PostThu Nov 19, 2009 6:19 pm
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Is d negative?

1. e+d=-12
2. e-d<12


Can someone please show me how to combine these two statements and arrive at the right answer? thanks.
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mridul_dave
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PostThu Nov 19, 2009 7:50 pm
okigbo wrote:
Is d negative?

1. e+d=-12
2. e-d<12


Can someone please show me how to combine these two statements and arrive at the right answer? thanks.
-e -d = 12 AND 12 > e - d
-e - d > e -d

Add 'd' to both sides. Inequality should hold true.

-e > e
0 > 2e
0> e implies e is negative


Given that e + d = 12
'd' MUST be positive and greater than 12 to make this happen.
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PostThu Nov 19, 2009 9:11 pm
I think it should be ‘E’

Each statement is not sufficient alone. Combining both the statements we get -

e = -12 - d
-12 - d - d < 12
-2d < 24

-d < 12 -> d > -12

d could be anything.
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PostThu Nov 19, 2009 9:22 pm
mridul_dave wrote:
okigbo wrote:
Is d negative?

1. e+d=-12
2. e-d<12


Can someone please show me how to combine these two statements and arrive at the right answer? thanks.
-e -d = 12 AND 12 > e - d
-e - d > e -d

Add 'd' to both sides. Inequality should hold true.

-e > e
0 > 2e
0> e implies e is negative


Given that e + d = 12
'd' MUST be positive and greater than 12 to make this happen.
Correction:

Given that e + d = -12 and e is negative, depending value of e, d can be both positive and negative. Silly mistake of sign before 12.
Agree answer is E.
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PostThu Nov 19, 2009 9:24 pm
okigbo wrote:
Is d negative?

1. e+d=-12
2. e-d<12


Can someone please show me how to combine these two statements and arrive at the right answer? thanks.
1. d = -12-e. Insufficient unless we know whether e < -12
2. d > -12 + e. Insufficient


Combined: -12-d-d < 12
-24 < 2d
-12 < d. Insufficient

E is the answer
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PostThu Nov 19, 2009 10:27 pm
I think C is the correct answer
1+2
yields e<0, and from 1 we know that e+d=-12 thus e+d<0 then d<-e since e<0 then d>0
any suggestions
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PostFri Nov 20, 2009 10:08 am
C is the OA.

adam15, can you show step by step of how you combined both statements to arrive at C?
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PostMon Nov 23, 2009 12:39 pm
please explain further.

adam15 wrote:
I think C is the correct answer
1+2
yields e<0, and from 1 we know that e+d=-12 thus e+d<0 then d<-e since e<0 then d>0
any suggestions
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PostMon Nov 23, 2009 12:51 pm
Guys, I think, the answer I provided is wrong, the mridul_dave is the right answer "E"
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PostMon Nov 23, 2009 3:54 pm
adam15 wrote:
I think C is the correct answer
1+2
yields e<0, and from 1 we know that e+d=-12 thus e+d<0 then d<-e since e<0 then d>0
any suggestions
if e < 0 and d < -e, d could still be positive or negative.

For example, if e=-5, we get d < -(-5) or d < 5, which could be positive or negative.

Back to the question:

1. e+d=-12
2. e-d<12

Assuming we all agree that they're not sufficient independently, let's jump right to combination.

Combined, we could pick e=-5 and d=-7, since:

-5 + (-7) = -12
and
-5 - (-7) = 2 < 12

Is -7 negative? YES

However, we can also pick e = -15 and d = +3, since:

-15 + 3 = -12
and
-15 - 3 = -12 < 12

Is +3 negative? NO

Since we can get both a YES and a NO answer, we don't have enough information to answer the question: choose E.
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PostThu Dec 03, 2009 1:58 am
from 1:
e = -12-d
from 2:
e-d<12
or, -12-d-d<12
or, -2d<24
or, -d<12
or, d>12

so d is not negative.
thus C is correct, which is the OA.
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PostThu Dec 03, 2009 2:33 pm
wanttobeat wrote:
from 1:
e = -12-d
from 2:
e-d<12
or, -12-d-d<12
or, -2d<24
or, -d<12
or, d>12
so d is not negative.
thus C is correct, which is the OA.
When you did your last step, you forgot to add the negative sign:

-d < 12

becomes

d > -12

So, d could be either positive or negative... choose E.
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