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If a b, what is the value of a + b? (1) a^2 - b^2 = 6 (2) ab = 12 Updated on: 27 Mar 2022, 02:03
Originally posted by Hoozan on 24 Mar 2022, 01:45.
Last edited by Hoozan on 27 Mar 2022, 02:03, edited 1 time in total.
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35% (medium)

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66% (01:06) correct 34% (01:34) wrong based on 77 sessions

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If a ≠ b, what is the value of a + b?

(1) a^2 - b^2 = 0
(2) ab = 12

This Question is Locked Due to Poor Quality
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Hoozan
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If a b, what is the value of a + b? (1) a^2 - b^2 = 6 (2) ab = 12 24 Mar 2022, 01:46
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Similar Question: https://gmatclub.com/forum/if-a-b-what- ... 08684.html
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If a b, what is the value of a + b? (1) a^2 - b^2 = 6 (2) ab = 12 26 Mar 2022, 14:40
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The solution to the question as it currently stands is incorrect. The answer should be E.

Question: If a ≠ b, what is the value of a + b?

(1) a^2 - b^2 = 6
This can further be broken down into:
(a+b)(a-b) = 6
We cannot get a numerical answer for this.

(2) ab = 12
Here we can many solutions including fractions and negatives:
2*6
36*1/3

Taking the two together once again we don't have an answer.
Please check the question or let me know if I am missing something.
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If a b, what is the value of a + b? (1) a^2 - b^2 = 6 (2) ab = 12 27 Mar 2022, 02:03
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Charli08
The solution to the question as it currently stands is incorrect. The answer should be E.

Question: If a ≠ b, what is the value of a + b?

(1) a^2 - b^2 = 6
This can further be broken down into:
(a+b)(a-b) = 6
We cannot get a numerical answer for this.

(2) ab = 12
Here we can many solutions including fractions and negatives:
2*6
36*1/3

Taking the two together once again we don't have an answer.
Please check the question or let me know if I am missing something.


I have made the changes to the question. the (1) statement says a^2 - b^2 = 0 and not "6"
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If a b, what is the value of a + b? (1) a^2 - b^2 = 6 (2) ab = 12 15 May 2023, 12:36
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(1) a^2 - b^2 = 0

(a-b)(a+b)=0

so either a-b=0 or a+b=0 but a-b can't be zero ( Given a ≠ b)
A = Suff

(2) ab = 12
a x b = 3 x 4 or 12 x 1 or 6x2 , multiple answers are possible so B = Insufficient
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If a b, what is the value of a + b? (1) a^2 - b^2 = 6 (2) ab = 12 21 Jan 2024, 04:46
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Hoozan
If a ≠ b, what is the value of a + b?

(1) a^2 - b^2 = 0
(2) ab = 12

Hoozan
I think both the statements are inconsistent with each other. As per statement 1, we know a+b=0 (also sufficient statement)
Now for statement 2 analysis, if -
(a+b)^2= a^2 + b^2 +2ab = 0 (from 1)
so, a^2 + b ^2 = -24 ----> Not possible as the sum of 2 squares can't be negative.

As far as I know even if one of the statements is insufficient, they shouldn't be inconsistent with each other.
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If a b, what is the value of a + b? (1) a^2 - b^2 = 6 (2) ab = 12 21 Jan 2024, 11:08
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SamzayWarrior
Hoozan
If a ≠ b, what is the value of a + b?

(1) a^2 - b^2 = 0
(2) ab = 12

Hoozan
I think both the statements are inconsistent with each other. As per statement 1, we know a+b=0 (also sufficient statement)
Now for statement 2 analysis, if -
(a+b)^2= a^2 + b^2 +2ab = 0 (from 1)
so, a^2 + b ^2 = -24 ----> Not possible as the sum of 2 squares can't be negative.

As far as I know even if one of the statements is insufficient, they shouldn't be inconsistent with each other.

a^2 - b^2 = 0 and ab = 12 has two sets of (a, b) satisfying it: \(a = -2\sqrt{3}, \ b = -2\sqrt{3}\) and \(a = 2\sqrt{3}, \ b =2\sqrt{3}\). However, for both of these sets, a = b, which contradicts the info given in the stem.

So, yes, you are right, the question is flawed. Tagging it as Poor Quality and locking.

Thank you!

This Question is Locked Due to Poor Quality
Hi there,
The question you've reached has been archived due to not meeting our community quality standards. No more replies are possible here.
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