Data Sufficiency

kshin78 wrote:

Why u r considering 'z' & 'm' as positive???
Consider
m= -4, z= -2

Now solve...

1) m-3z>0
-4 + 6 = 2, which is greater than 0

2) 4z-m<0
-8 +4 = -4, which is less than 0

doesn't value for m & z both satisfy 1 as well as 2

Now would u say that combining both statements we get both 'z' and 'm' as negative.
So we can't assume them positive.?????

moreover que doesn't say that m and v are positive...
I'm not assuming anything.....[/quote]


i'm so with you Suyog... i can't seem to figure it out...

the argument here is that m> 0 because z > 0. ok, true if z > 0, but WHY??? We can't assume that z > 0 when there are negative values that holds true for both equations.[/quote]

BTW..just saw this error as part of Sentence correction. it should be "negative values that hold" ... i know this is not a verbal section but just practicing...lol

I feel that from these eqn:

If a)+b) implies m>0 ie M is positve (we cant take the negative numbers)

from eqn a) I can say m >3z

from eqn b) I can say m <4z

from this we can deduce 3z<m<4z;


So answer shld be C.

Pls let me know if I am wrong .. bcos I can be

Is m+z>0?

1) m-3z>0
2) 4z-m<0

I agree that the answer should be (E).

Even taking both statements into account, we could choose:

m = 4, z = 1/3, since

1) 4 - 1 > 0
and
2) 4/3 - 4 < 0

to get a "yes" answer, and

m = -1 and z = -5, since

1) -1 - (-15) > 0
and
2) -60 - (-1) < 0

to get a "no" answer.

It's very important to remember that we CANNOT treat inequalities as we do equations.

For example, we cannot simply add or subtract two inequalities, as some have tried to do in this thread. Let's look at a more concrete example:

x + 3 > 0
x + 5 > 0

Clearly, these two statements could both be true (and will be true for all x > -5). However, if we subtract the second from the first, we'd get:

-2 > 0

which obviously makes no sense.

edited because my example need fixin'!

Absolutely gr8!!!! :twisted:
A BIG Thank you Stuart

Stuart Kovinsky wrote:

Is m+z>0?

1) m-3z>0
2) 4z-m<0

I agree that the answer should be (E).




It's very important to remember that we CANNOT treat inequalities as we do equations.

For example, we cannot simply add or subtract two inequalities, as some have tried to do in this thread. Let's look at a more concrete example:

x + 3 > 0
x - 5 > 0

Clearly, these two statements could both be true (and will be true for all x > 5). However, if we subtract the second from the first, we'd get:

-2 > 0

which obviously makes no sense.

This is a good learning for me , i agree for sure, that inequalities can't be solved like equations !!

Amit

I think E.

question: m+z>0? or m>-z?

(1) m-3z>0, or m>3z. So what? They are positive or negative?
(1) 4z-m<0, or m>4z. So what? They are positive or negative? (2) is the same as (1)

(1) and (2)
still insuffucient. E.

Why C?

Absolutely guys , the point which was causing trouble all along was how did sudhir & amit get to a conclusion than z is>0 ,

because combining the 2 inequalities we get only m>3Z & m>4z which are insufficient to prove z> 0

I guess I still stick to E !!

whats the OA by the way anyone??

raptor84 wrote:IS m+z>0

1) m-3z>0
2) 4z-m<0


OA C

Hell Raptor84! you have posted wrong question and wasted everyone's time. The second equation that you have posted is wrong. It should be 4z-m > 0

Guys, correct question is posted over here.

https://www.beatthegmat.com/m-z-0-t15944.html

And yes inequalities can be added if they have same sign and (C) is the correct answer.