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03 Sep 2017, 06:23
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B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
75% (01:26) correct
25%
(01:37)
wrong
based on 257
sessions
History
Date
Time
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Not Attempted Yet
What is the value of x^2 – y^2 ?
(1) x + y = 2y – 1
(2) 5x - 5y = 1/(2x + 2y)
(1) x + y = 2y – 1
(2) 5x - 5y = 1/(2x + 2y)
chipsy
Joined: 05 Oct 2014
Last visit: 01 Sep 2021
Posts: 55
Own Kudos:
Given Kudos: 149
Concentration: Technology, Entrepreneurship
Schools: Tepper '23 Ross '23 McCombs '23 Tuck '23 NUS '23
03 Sep 2017, 06:47
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We need to find x^2 - y^2 = (x-y) (x+y)
(A) x - y = -1 , Not suff.
(B) 5x - 5y = 1/(2x + 2y)
5 (x-y) * 2(x+y) = 1
10 (x-y) (x+y) =1
(x-y) (x+y) = 1/10
Sufficient.
answer is Option B.
(A) x - y = -1 , Not suff.
(B) 5x - 5y = 1/(2x + 2y)
5 (x-y) * 2(x+y) = 1
10 (x-y) (x+y) =1
(x-y) (x+y) = 1/10
Sufficient.
answer is Option B.
03 Sep 2017, 06:55
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Fine x^2-y^2 (x+y)(x-y)
1) x+y=2y-1
=> x-y=-1
even if we multiply both => (x+y)(x-y)= -(2y-1)
Not sufficient
2)5x - 5y = 1/(2x + 2y)
=> 5(x-y) =1/(2x + 2y)
=> 5(x-y) *(2x + 2y)=1
=>5(x-y)*2(x+y)=1
> (x-y)(x+y)=1/10
Sufficient
Answer: B
1) x+y=2y-1
=> x-y=-1
even if we multiply both => (x+y)(x-y)= -(2y-1)
Not sufficient
2)5x - 5y = 1/(2x + 2y)
=> 5(x-y) =1/(2x + 2y)
=> 5(x-y) *(2x + 2y)=1
=>5(x-y)*2(x+y)=1
> (x-y)(x+y)=1/10
Sufficient
Answer: B
