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If a, b, and c are integers, what is the value of a?
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Updated on: 13 Oct 2014, 03:18
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If a, b, and c are integers, what is the value of a? (1) (a  7)(b  7)(c  7) = 0 (2) bc = 18
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Originally posted by snowbirdskier on 05 Dec 2008, 20:25.
Last edited by Bunuel on 13 Oct 2014, 03:18, edited 1 time in total.
Renamed the topic, edited the question and added the OA.




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Re: If a, b, and c are integers, what is the value of a?
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29 Nov 2015, 16:20
Hi All, This is a great 'concept' question, and it doesn't require much math to solve it. We're told that A, B and C are all integers. We're asked for the value of A. 1) (A  7)(B  7)(C  7) = 0 With this Fact, we know that AT LEAST one of the variables MUST equal 7, while the other two variables could be ANY integer. Thus, A could be 7, but it could also be any other integer. Fact 1 is INSUFFICIENT 2) BC = 18 This Fact tells us NOTHING about the value of A. Fact 2 is INSUFFICIENT Combined, we know... (A  7)(B  7)(C  7) = 0 BC = 18 From the second Fact (AND that the variables are all INTEGERS), neither B nor C can equal 7. If either of those variables was 7, then the other variable would have to be 18/7, which is NOT an option). Since those 2 variables CANNOT be 7, the variable A MUST be 7 (to satisfy the first Fact). Combined, SUFFICIENT. Final Answer: GMAT assassins aren't born, they're made, Rich
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Re: If a, b, and c are integers, what is the value of a?
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05 Dec 2008, 21:48
My Answer is also C. But slightly from a differnt understanding.
Clue 1  either a or b or c can be zero. So we cannot say the value for a. INSUFF
Clue 2  bc = 18 means possible values for B and C are 1,2,3,6,9,18. No way we can say the value for A. So Insufficient.
Now considering both the clues, since B and C 1,2,3,6,9,18, to satisfy Clue 1, a should be 7. With both the clues, we can find the value for A.




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Re: If a, b, and c are integers, what is the value of a?
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05 Dec 2008, 21:09
C
1) (a7)(b7)(c7)=0 ; any of the integer a,b,c should be 7 ; but we cant say which one. INSUFF 2) bc=18 ; so bc Ne 0; doesn't give any clue!!
combine both, we know b, c ne 0, so a should be 7.



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Re: If a, b, and c are integers, what is the value of a?
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08 Dec 2008, 12:18
Thanks for the help but still not getting it. If bc ne 0 doesn't one of them have to = 0 leaving only A to equal 0?



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Re: If a, b, and c are integers, what is the value of a?
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08 Dec 2008, 12:55
snowbirdskier wrote: Thanks for the help but still not getting it. If bc ne 0 doesn't one of them have to = 0 leaving only A to equal 0? from (2), if bc =18 > both b and c can not be 7 as 18 does not have 7 as factor from (1), which means that (b7) and (c7) are not equal to 0 which means that a7 = 0 > a =7 Hence answer is (c)
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Re: If a, b, and c are integers, what is the value of a?
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27 Nov 2015, 08:49
(1) (a7)(b7)(c7) = 0
3 variables, 1 equation = insufficient
(2) bc=18
2 variables, 1 equation = insufficient
Combined:
3 variables, 2 equations, and you could substitute bc and be left with a
Answer: C



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Re: If a, b, and c are integers, what is the value of a?
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23 Dec 2016, 14:02
If a, b, and c are integers, what is the value of a?
(1) (a  7)(b  7)(c  7) = 0 (2) bc = 18
This is my understanding. (1) a =7, b = 7, c= 7 ( a,b,c are integers NOT distinct integers) So a or b or c does not have to be equal to 7.
(2) bc = 18 (a cannot be found from this equation)
Ans: A.



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Re: If a, b, and c are integers, what is the value of a?
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23 Dec 2016, 15:41
Hi nsarmah1, You have to be careful about how you use the information that you've been given. In Fact 1, we're told that (A  7)(B  7)(C  7) = 0. That does NOT mean that all three variables equal 7; it means that AT LEAST ONE of the variables equals 7. If B=7, the A could be ANY value. As such, Fact 1 is insufficient on its own. GMAT assassins aren't born, they're made, Rich
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Re: If a, b, and c are integers, what is the value of a?
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08 Sep 2019, 03:43
Hi EMPOWERgmatRichC VeritasKarishma Bunuel chetan2u GMATPrepNowIs below approach correct to combine both statements: Facts: 1. If product of bc is not zero, the none of b or c can be equal to 0. 2. A product of two no = 18 suggests that 7 is not a factor of 18 since we are given a, b c are integers. From fact 2 , I can conclude that (a7) MUST BE equal to 0 since b/c can not be equal to 0 (fact 1). Is this correct, or seems too complicated?
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Re: If a, b, and c are integers, what is the value of a?
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08 Sep 2019, 06:09
adkikani wrote: Hi EMPOWERgmatRichC VeritasKarishma Bunuel chetan2u GMATPrepNowIs below approach correct to combine both statements: Facts: 1. If product of bc is not zero, the none of b or c can be equal to 0. 2. A product of two no = 18 suggests that 7 is not a factor of 18 since we are given a, b c are integers. From fact 2 , I can conclude that (a7) MUST BE equal to 0 since b/c can not be equal to 0 (fact 1). Is this correct, or seems too complicated? Yes, that's solid reasoning. I would add to your second point that, if bc = 18, then neither b nor c can equal 7 .
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If a, b, and c are integers, what is the value of a?
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08 Sep 2019, 07:53
snowbirdskier wrote: If a, b, and c are integers, what is the value of a?
(1) (a  7)(b  7)(c  7) = 0 (2) bc = 18 Given: a, b, and c are integers Asked: What is the value of a? (1) (a  7)(b  7)(c  7) = 0 means either a or b or c = 7 But it does not mean that a must be 7 NOT SUFFICIENT (2) bc = 18 Value of (b,c) pairs = {(1,18),(2,9),(3,6),(6,3),(9,2),(18,1)} NOT SUFFICIENT Combining (1) & (2) (1) (a  7)(b  7)(c  7) = 0 means either a or b or c = 7 (2) bc = 18 Value of (b,c) pairs = {(1,18),(2,9),(3,6),(6,3),(9,2),(18,1)} It means that b & c are NOT = 7 a = 7 SUFFICIENT IMO C
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Re: If a, b, and c are integers, what is the value of a?
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08 Sep 2019, 15:45
adkikani wrote: Hi EMPOWERgmatRichC VeritasKarishma Bunuel chetan2u GMATPrepNowIs below approach correct to combine both statements: Facts: 1. If product of bc is not zero, the none of b or c can be equal to 0. 2. A product of two no = 18 suggests that 7 is not a factor of 18 since we are given a, b c are integers. From fact 2 , I can conclude that (a7) MUST BE equal to 0 since b/c can not be equal to 0 (fact 1). Is this correct, or seems too complicated? Hi adkikani, YES  that is exactly correct. GMAT assassins aren't born, they're made, Rich
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Re: If a,b, and c are integers, what is the value of a? I
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