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Manager
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If a>0, b>0, c>0, Is a(b-c)=0 1) b-c=c-b 2) b/c=c/b [#permalink]
 06 Jun 2008, 11:19
If a>0, b>0, c>0, Is a(b-c)=0
1) b-c=c-b
2) b/c=c/b
I don't have an OA, but want to verify my answer. Thanks.
Soomodh
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Director
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I think each one is suff. (D)
(1) gives b=c. So suff. for any a.
(2) gives b=c or b=-c, but, taken together with the condition b>0, c>0, it gives b=c. Suff.
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Manager
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Greenoak, thanks thats what I got (I initially got wrong coz I didn't realize greater than zero condition).
S
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Intern
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Hi guys,
I got D.
1) b - c = c - b
or 2B = 2C, B = C. any value of a * (b - c) will be 0 .suff
2) b/c = c/b
= c^2 = b^2
or c = b , again same analysis. suff.
if my logic is incorrect, please let me know.
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Manager
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ca_gold careful with c2= b2 , so c= b statement, this is only true if c and b are positive, if -ve then not.
Soomodh
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Manager
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It's D.
Statement (1) is straight forward.
Lets look at statement (2)
\frac {b} {c} = \frac {c} {b}
or b^2=c^2
or b^2-c^2=0
or (b+c)(b-c)=0
which gives us eitherb=c, or b=-c
Since we know from the question stem that b>0, c>0, we can ignore b=-c
Therefore, statement (2) is also sufficient.
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soomodh wrote: ca_gold careful with c2= b2 , so c= b statement, this is only true if c and b are positive, if -ve then not.
Soomodh hi soomodh, good call, thanks for the that!
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