rohit8865 wrote:

chetan2u wrote:

fattty wrote:

ㅣs – tㅣ > ㅣㅣsㅣ - ㅣtㅣㅣ?

1) s + t < 0

2) st < 0

Hi..

when we look at the equation, what stands out is-

1) If both s and t are of same sign, the answer to the Q is NO, as both will be equal.. and suff

2) If both have different signs, answer is YES... SUff..

lets see the choices..

1) s + t < 0

both s and t can be negative.. or both can be of different sign.. insuff

2) st < 0

both s and t are of different sign .. suff as per the condition 20 mentioned above..

B

Chetan

could you please elaborate it for me ...??

Hi Rohit,

lets see what the statement tells us..

ㅣs – tㅣ > ㅣㅣsㅣ - ㅣtㅣㅣ...

1) If both s and t are of same sign, the answer to the Q is NO, as both will be equal.. and sufflets take s as 4 and t as 5..

|4-5|>||4|-|5||..

|-1|>|-1|... 1>1.. NO

lets take them -ive now s=-4 and t=-5..

|-4-(-5)|>||-4|-|-5||..

|1|>|-1|... 1>1.. NO

so whatever values we take for s and t, if they both are of same sign, the two sides will be equal..

so our answer for [b]ㅣs – tㅣ > ㅣㅣsㅣ - ㅣtㅣㅣ is NO.. and thus suff..[/b]

2) If both have different signs, answer is YES... SUff..say s=4 and t=-5..

|4-(-5)|>||4|-|-5||..

|9|>|-1|... 9>1.. yes..

you can take any values for s and t but of different signs , you will always get YES for

ㅣs – tㅣ > ㅣㅣsㅣ - ㅣtㅣㅣ..

so what do we require to know, just that the signs of s and t is same or different and we will be able to answer for

is ㅣs – tㅣ > ㅣㅣsㅣ - ㅣtㅣㅣ?now lets see the statements..

1) s + t < 0We cannot say anything about signs

both s and t can be negative.. or both can be of different sign.. insuff

2) st < 0both s and t are of different sign, then only the product will be <0..

-a*-b= +ab

+a*+b=+ab, but -a*+b=-ab

.. suff as per the condition (2) mentioned above..

I hope it helps

_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372

2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

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