This if from OG
If x,y, and z are positive numbers, is x > y > z ?
1) xz > yz
2) yx > yz
x,y and z are positive integers(numbers) and we have to determine if x > y and y > z
From 1) : as z is positive the inequality can be divided by z on both sides, thus x > y
Not sufficient.
From 2) : again as y is positive x > z
Not sufficient.
1&2 both :
one way to combine - x > y and x > z, we are still not able to find whether y > z. Not sufficient. OA for this is E and OE is similar to above.
My doubt is regarding statements 1&2 combined.
I think we can also divide the inequalities here.
So (1)/(2) = xz/yx > yz/yz => z / y > 1 => as z and y are integers z > y
This is sufficient to determine that x,z > y, at least we know z > y and y is not > z thus it is sufficient to answer the question.
Combining inequalities is even done in OG explanation. Is the division method wrong to follow?
Please share your thoughts.
Thanks.
x,y and z
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- anshumishra
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You can't do that, here is why :beat_gmat_09 wrote:This if from OG
If x,y, and z are positive numbers, is x > y > z ?
1) xz > yz
2) yx > yz
x,y and z are positive integers(numbers) and we have to determine if x > y and y > z
From 1) : as z is positive the inequality can be divided by z on both sides, thus x > y
Not sufficient.
From 2) : again as y is positive x > z
Not sufficient.
1&2 both :
one way to combine - x > y and x > z, we are still not able to find whether y > z. Not sufficient. OA for this is E and OE is similar to above.
My doubt is regarding statements 1&2 combined.
I think we can also divide the inequalities here.
So (1)/(2) = xz/yx > yz/yz => z / y > 1 => as z and y are integers z > y
This is sufficient to determine that x,z > y, at least we know z > y and y is not > z thus it is sufficient to answer the question.
Combining inequalities is even done in OG explanation. Is the division method wrong to follow?
Please share your thoughts.
Thanks.
6 > 5
7 > 5
Can I do 6/7 > 5/5
or 6/7 > 1
No, Right ? Because in an inequality we don't know by how much LHS can be greater/smaller than RHS.
OR
7/6 > 5/5
7/6 > 1 (Here we are just lucky, that the inequality still holds).
Thanks
Anshu
(Every mistake is a lesson learned )
Anshu
(Every mistake is a lesson learned )
- goyalsau
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Great work guys,
Beat_gmat_09, Has shown a very good point. Anshu Has given a very good explanation.
I just wan't to ask one thing.?
If x > z & p > q
then we can add the inequality and subtract , Irrespective of there signs.
We can do x + p > z + q & x - p > z - q or p - x > q - z
we can not divide but Can we do the multiplication of as well.
Beat_gmat_09, Has shown a very good point. Anshu Has given a very good explanation.
I just wan't to ask one thing.?
If x > z & p > q
then we can add the inequality and subtract , Irrespective of there signs.
We can do x + p > z + q & x - p > z - q or p - x > q - z
we can not divide but Can we do the multiplication of as well.
Saurabh Goyal
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EveryBody Wants to Win But Nobody wants to prepare for Win.
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EveryBody Wants to Win But Nobody wants to prepare for Win.
- anshumishra
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Lets take an example :goyalsau wrote:Great work guys,
Beat_gmat_09, Has shown a very good point. Anshu Has given a very good explanation.
I just wan't to ask one thing.?
If x > z & p > q
then we can add the inequality and subtract , Irrespective of there signs.
We can do x + p > z + q & x - p > z - q or p - x > q - z
we can not divide but Can we do the multiplication of as well.
5 > -5
-1 > -5
Multiply the inequalities :
-5 > 25 (Not right)...
So you can't always multiply. Check the sign if you do.
Thanks
Anshu
(Every mistake is a lesson learned )
Anshu
(Every mistake is a lesson learned )
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Picking numbers was my last resort, actually i tended avoid it to save time for this question, but its better to go with numbers and check. One should be careful when multiplying/dividing inequalities.anshumishra wrote:
You can't do that, here is why :
6 > 5
7 > 5
Can I do 6/7 > 5/5
or 6/7 > 1
No, Right ? Because in an inequality we don't know by how much LHS can be greater/smaller than RHS.
OR
7/6 > 5/5
7/6 > 1 (Here we are just lucky, that the inequality still holds).
@goyalsau: anshumishra is right on multiplying. Its safe to add/subtract inequalities, but not safe to divide/multiply.
In this question all the three variables were +ve and division was no harm, still the combination didn't work.
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