What is the ratio of r to s?
(1) r + s = 7
(2) r^2 - s^2 = 7
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(1) r, s can take many values so that r + s = 7, viz., r = 4, s = 3, r = 2, s = 5, r = 1, s = 6 and so on. We don't have a definite answer; NOT sufficient.anujmalik wrote:What is the ratio of r to s?
(1) r + s = 7
(2) r^2 - s^2 = 7
(2) r² - s² = 7 or (r + s)(r - s) = 7
Now, r = 4, s = 3 then r : s = 4 : 3
r = 4, s = -3 then r : s = 4 : -3
No definite answer; NOT sufficient.
Combining (1) and (2), the only possible value of r = 4 and s = 3, so r : s = 4 : 3
The correct answer is C.
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Hi Anurag,
I tried to solve it in a different way and got E. Could you please help me understand where am i going wrong?
Statement(1): r + s = 7
picking numbers: r = 3, s = 4 and r = 4, s = 3 we can say that St (1) is NOT sufficient
Statement(2): r^2 - s^2 = 7
(r-s)*(r+s)= 7
Again picking numbers r = 4, s = 3 and r = 4, s = -3 we can say that St (2) is NOT sufficient
Combining (1) and (2)
(r-s)*(r+s)= 7
(r-s)*7= 7
r-s = 1
So both options together are NOT sufficient.
Am I doing something wrong?
I tried to solve it in a different way and got E. Could you please help me understand where am i going wrong?
Statement(1): r + s = 7
picking numbers: r = 3, s = 4 and r = 4, s = 3 we can say that St (1) is NOT sufficient
Statement(2): r^2 - s^2 = 7
(r-s)*(r+s)= 7
Again picking numbers r = 4, s = 3 and r = 4, s = -3 we can say that St (2) is NOT sufficient
Combining (1) and (2)
(r-s)*(r+s)= 7
(r-s)*7= 7
r-s = 1
So both options together are NOT sufficient.
Am I doing something wrong?
Anurag@Gurome wrote:(1) r, s can take many values so that r + s = 7, viz., r = 4, s = 3, r = 2, s = 5, r = 1, s = 6 and so on. We don't have a definite answer; NOT sufficient.anujmalik wrote:What is the ratio of r to s?
(1) r + s = 7
(2) r^2 - s^2 = 7
(2) r² - s² = 7 or (r + s)(r - s) = 7
Now, r = 4, s = 3 then r : s = 4 : 3
r = 4, s = -3 then r : s = 4 : -3
No definite answer; NOT sufficient.
Combining (1) and (2), the only possible value of r = 4 and s = 3, so r : s = 4 : 3
The correct answer is C.
Oops.. combining (1) and (2)
(r-s)*(r+s)= 7
(r-s)*7= 7
r-s = 1
Again r+s = 7
2r = 8
r = 4 and s 7-4 = 3
C is the Answer...
(r-s)*(r+s)= 7
(r-s)*7= 7
r-s = 1
Again r+s = 7
2r = 8
r = 4 and s 7-4 = 3
C is the Answer...
GAMATO wrote:Hi Anurag,
I tried to solve it in a different way and got E. Could you please help me understand where am i going wrong?
Statement(1): r + s = 7
picking numbers: r = 3, s = 4 and r = 4, s = 3 we can say that St (1) is NOT sufficient
Statement(2): r^2 - s^2 = 7
(r-s)*(r+s)= 7
Again picking numbers r = 4, s = 3 and r = 4, s = -3 we can say that St (2) is NOT sufficient
Combining (1) and (2)
(r-s)*(r+s)= 7
(r-s)*7= 7
r-s = 1
So both options together are NOT sufficient.
Am I doing something wrong?
Anurag@Gurome wrote:(1) r, s can take many values so that r + s = 7, viz., r = 4, s = 3, r = 2, s = 5, r = 1, s = 6 and so on. We don't have a definite answer; NOT sufficient.anujmalik wrote:What is the ratio of r to s?
(1) r + s = 7
(2) r^2 - s^2 = 7
(2) r² - s² = 7 or (r + s)(r - s) = 7
Now, r = 4, s = 3 then r : s = 4 : 3
r = 4, s = -3 then r : s = 4 : -3
No definite answer; NOT sufficient.
Combining (1) and (2), the only possible value of r = 4 and s = 3, so r : s = 4 : 3
The correct answer is C.
GMAT/MBA Expert
- Anurag@Gurome
- GMAT Instructor
- Posts: 3835
- Joined: Fri Apr 02, 2010 10:00 pm
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- GMAT Score:770
That's right. You answered it on your ownGAMATO wrote:Oops.. combining (1) and (2)
(r-s)*(r+s)= 7
(r-s)*7= 7
r-s = 1
Again r+s = 7
2r = 8
r = 4 and s 7-4 = 3
C is the Answer...
GAMATO wrote:Hi Anurag,
I tried to solve it in a different way and got E. Could you please help me understand where am i going wrong?
Statement(1): r + s = 7
picking numbers: r = 3, s = 4 and r = 4, s = 3 we can say that St (1) is NOT sufficient
Statement(2): r^2 - s^2 = 7
(r-s)*(r+s)= 7
Again picking numbers r = 4, s = 3 and r = 4, s = -3 we can say that St (2) is NOT sufficient
Combining (1) and (2)
(r-s)*(r+s)= 7
(r-s)*7= 7
r-s = 1
So both options together are NOT sufficient.
Am I doing something wrong?
Anurag@Gurome wrote:(1) r, s can take many values so that r + s = 7, viz., r = 4, s = 3, r = 2, s = 5, r = 1, s = 6 and so on. We don't have a definite answer; NOT sufficient.anujmalik wrote:What is the ratio of r to s?
(1) r + s = 7
(2) r^2 - s^2 = 7
(2) r² - s² = 7 or (r + s)(r - s) = 7
Now, r = 4, s = 3 then r : s = 4 : 3
r = 4, s = -3 then r : s = 4 : -3
No definite answer; NOT sufficient.
Combining (1) and (2), the only possible value of r = 4 and s = 3, so r : s = 4 : 3
The correct answer is C.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
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GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
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