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If a,b, and C are integers, is ab+c greater than a+bc? 1) [#permalink]
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01 Mar 2007, 02:27
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If a,b, and C are integers, is ab+c greater than a+bc?
1) b is negative
2) c is positive



Director
Joined: 06 Feb 2006
Posts: 897

I think C
The question essiantially asks whether b<c
1) not sufficient
2) not sufficient
1)+2) obviously sufficient



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DS: Integers [#permalink]
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22 Oct 2007, 07:06
If a,b, and c are integers, is a – b + c greater than a + b – c ?
(1) b is negative.
(2) c is positive.



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Re: DS: Integers [#permalink]
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22 Oct 2007, 07:29
sidbidus wrote: If a,b, and c are integers, is a – b + c greater than a + b – c ?
(1) b is negative. (2) c is positive.
From question stem, a + b  c < a  b + c
2b < 2c
b < c
As a result, we only need to prove that b < c
1. b < 0, no info about c, INSUFF
2. c > 0, no info about b, INSUFF
1. + 2.) Clearly b (negative) < c (positive), SUFF
The answer is (C)



Senior Manager
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Somehow the OA is (A). Can anyone explain why???



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Joined: 07 Jul 2004
Posts: 5043
Location: Singapore

Case1:
ab+c > a+bc?
2b > 2c?
b < c?
Case2:
ab+c < a+bc
2b < 2c
b > c
St1:
If b = 1 and c = 2, then ab+c > a+bc
If b = 1 and c = 2, then ab+c < a+bc
Insufficient.
St2:
If c = 2, and b = 1, then ab+c > a+bc
If c = 2 and b = 3, then ab+c < a+bc
Insufficient.
St1 and St2:
If c is positive and b is negative, then b<c and so ab+c > a+bc. Sufficient.
I go for C too.



Intern
Joined: 09 Oct 2007
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sidbidus wrote: Somehow the OA is (A). Can anyone explain why???
OA is not A. This is the question 17 from OG 10, DS Sample Set, page 238. OA is C.



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DS integers [#permalink]
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26 Jan 2008, 14:12
If a, b and c are integers, is ab+c greater than a+bc ?
(1) b is negative (2) c is positive



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Joined: 22 Sep 2005
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Re: DS integers [#permalink]
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26 Jan 2008, 14:30
blog wrote: If a, b and c are integers, is ab+c greater than a+bc ?
(1) b is negative (2) c is positive C ab+c > a+bc. Then aa+2c > 2b. They ask if c>b 1) INSUF because we don't know anything about b 2) INSUF " " c Both together, SUF



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DS pos/neg [#permalink]
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05 Jul 2008, 14:38
If a,b, and c are integers, is a – b + c greater than a + b – c ? (1) b is negative. (2) c is positive.



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Re: DS pos/neg [#permalink]
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05 Jul 2008, 17:02
Quote: If a,b, and c are integers, is a – b + c greater than a + b – c ? (1) b is negative. (2) c is positive. If we transform the inequality, we can see that the question asks us whether b<c. (transformation: a – b + c > a + b – c <=>  b+c > bc <=> c>b) St 1. doesn’t help us to answer the question – c could be anything, and thus we can conclude nothing about the inequality. You can construct examples if you like. Similarly, St 2. is also insufficient. Together: b<0<c => b<c => inequality is true. Hence, C.



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Re: DS pos/neg [#permalink]
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05 Jul 2008, 20:39
I think its C. The question is basically asking you to determine if c > b .
From stat 1, you know b is neg, but you dont know if c>b, i.e. c=2 and b=1, or c=1 and b=2. Insuff.
Same argument for stat 2.
Together, you know that c>b since c is positive and b is negative



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Re: DS pos/neg [#permalink]
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06 Jul 2008, 07:43
greenoak wrote: Quote: If a,b, and c are integers, is a – b + c greater than a + b – c ? (1) b is negative. (2) c is positive. If we transform the inequality, we can see that the question asks us whether b<c. (transformation: a – b + c > a + b – c <=>  b+c > bc <=> c>b) St 1. doesn’t help us to answer the question – c could be anything, and thus we can conclude nothing about the inequality. You can construct examples if you like. Similarly, St 2. is also insufficient. Together: b<0<c => b<c => inequality is true. Hence, C. I used the same approach



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Number Properties [#permalink]
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10 Sep 2011, 11:34
Id a,b, and c are integers, is ab+c > a+bc ? 1) b is negative. 2) c is positive.
c>b, it is from the question after doing subtractions and additions, now my question is statement 2 is sufficient to answer the question. but the answer is not b. any one please explain.



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Re: Number Properties [#permalink]
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10 Sep 2011, 11:39
Is a  b + c > a + b  c => Is c > b ? Using statement (1): c could still be greater or lesser than b even if b is negative. Insufficient. Using statement (2): c could still be greater of lesser than b even if c is positive. Insufficient. Combining (1) and (2): If b is negative and c is positive then c is definitely greater than b. Sufficient. Answer (C)
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Re: Number Properties
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10 Sep 2011, 11:39








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