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abc≠0 and 3/a + 3/b = 3/c. What is the sum a+b? https://gmatclub.com/forum/abc0and3a3b3cwhatisthesumab240443.html 
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Author:  Bunuel [ 18 May 2017, 00:29 ] 
Post subject:  abc≠0 and 3/a + 3/b = 3/c. What is the sum a+b? 
abc≠0 and 3/a + 3/b = 3/c. What is the sum a+b? (1) ab=c (2) ab=ac+bc 
Author:  obliraj [ 18 May 2017, 00:55 ] 
Post subject:  Re: abc≠0 and 3/a + 3/b = 3/c. What is the sum a+b? 
Answer A. 3/a + 3/b = 3/c 1/a + 1/b = 1/c (a+b)/ab = 1/c a+b = ab/c St 1: ab = c ; i.e a+b=1 sufficient St 2: ab=ac+bc; ab=c(a+b); a+b=ab/c cannot find a+b Insufficient. 
Author:  Nunuboy1994 [ 20 May 2017, 07:37 ] 
Post subject:  Re: abc≠0 and 3/a + 3/b = 3/c. What is the sum a+b? 
obliraj wrote: Answer A. 3/a + 3/b = 3/c 1/a + 1/b = 1/c (a+b)/ab = 1/c a+b = ab/c St 1: ab = c ; i.e a+b=1 sufficient St 2: ab=ac+bc; ab=c(a+b); a+b=ab/c cannot find a+b Insufficient. It's because if the we know the product of a and b equals the numerator of 1/c or c then the top we can just set equal to a + b= 1 Hence A 
Author:  abhishekdadarwal2009 [ 05 Feb 2019, 11:49 ] 
Post subject:  Re: abc≠0 and 3/a + 3/b = 3/c. What is the sum a+b? 
abc≠0 and 3/a + 3/b = 3/c. What is the sum a+b? (1) ab=c (2) ab=ac+bc solution: 3/a+3/b=3/c =3(a+b)/ab=3/c. 1.ab=c ,substitute in the above equation we get a+b=1. A is sufficient 2.ab=c(a+b), substitute in equation above, we get 1/c so it provies the same info that we already know. so not sufficient A is the correct answer. 
Author:  bumpbot [ 24 Dec 2022, 04:47 ] 
Post subject:  Re: abc0 and 3/a + 3/b = 3/c. What is the sum a+b? 
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