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Source: — Data Sufficiency |
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by thephoenix » Fri Feb 19, 2010 4:29 am
daretodream wrote:If x not equal to -y, is (x-y)/(x+y) > 1?

(1) x>0
(2) y<0
simplifying (x-y)/(x+y)-1>0
-2y/(x+y)>0

if we know relation b/n x and y and whether its +ve or -ve we can find it

s1) we know only x>0 for x>y and for x<y we get diff ans

s2) same

combine suff

x>0>y
suff to tell whether the exp is> or not than 0
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by tata » Fri Feb 19, 2010 1:19 pm
thephoenix wrote:
daretodream wrote:If x not equal to -y, is (x-y)/(x+y) > 1?

(1) x>0
(2) y<0
simplifying (x-y)/(x+y)-1>0
-2y/(x+y)>0

if we know relation b/n x and y and whether its +ve or -ve we can find it

s1) we know only x>0 for x>y and for x<y we get diff ans

s2) same

combine suff

x>0>y
suff to tell whether the exp is> or not than 0

Fellas, this is how I see this

simplifying (x-y)/(x+y)-1>0
(x-y)/(x+y)>1
x-y>x+y
Or 2y<0
Or y<0

So question boils down to is Y<0


A is Insufficient, B is sufficient.


Am I doing anything wrong here?
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by harsh.champ » Fri Feb 19, 2010 1:33 pm
tata wrote:
thephoenix wrote:
daretodream wrote:If x not equal to -y, is (x-y)/(x+y) > 1?

(1) x>0
(2) y<0
simplifying (x-y)/(x+y)-1>0
-2y/(x+y)>0

if we know relation b/n x and y and whether its +ve or -ve we can find it

s1) we know only x>0 for x>y and for x<y we get diff ans

s2) same

combine suff

x>0>y
suff to tell whether the exp is> or not than 0

Fellas, this is how I see this

simplifying (x-y)/(x+y)-1>0
(x-y)/(x+y)>1
x-y>x+y
Or 2y<0
Or y<0

So question boils down to is Y<0


A is Insufficient, B is sufficient.


Am I doing anything wrong here?
Well you have transposed
(x-y)/(x+y)>1
TO
x-y>x+y
This can only be done if we know that the sum(x+y) is A +ve no.
Otherwise,the inequality sign will change.
It takes time and effort to explain, so if my comment helped you please press Thanks button :)



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by Amiman » Fri Feb 19, 2010 2:58 pm
1 and 2 insuff can be easily deduced

combine 1 and 2

if x = 2 and y = -3
then -2y/(x+y) = -2.-2/(2 - 3) = - 4 i.e. < 0

if x = 1 and y = -1/2
the (-2.-1/2)/(1 - 1/2) = 1/(1/2) = 2 i.e > 0

so not suff..

Hence E.
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by shashank.ism » Sun Feb 21, 2010 5:34 am
daretodream wrote:If x not equal to -y, is (x-y)/(x+y) > 1?

(1) x>0
(2) y<0
x=/= -y
St.1) x>0 --> but we don't know about y so insuff.
St.2) y<0 --> but we don't know about x so insuff.

combined) : x>0,y<0 --> (x-y)> x and x+y <x
so (x-y)/(x+y) > 1 Hence Suff. Ans C
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by girish3131 » Tue Mar 09, 2010 1:35 am
IMO B

plz post OA....

ta
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