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If (x – y)(x + y) = 15 and x + y = 5, then what is the valu
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04 Apr 2019, 04:12
04 Apr 2019, 04:12
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Question Stats:
88% (01:21) correct
11% (01:39) wrong based on 18 sessions
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If (x – y)(x + y) = 15 and x + y = 5, then what is the value of \(\frac{x}{y}\) ?
(A) 3
(B) 4
(C) 5
(D) 10
(E) 15
(A) 3
(B) 4
(C) 5
(D) 10
(E) 15
Re: If (x – y)(x + y) = 15 and x + y = 5, then what is the valu
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14 Apr 2020, 09:30
14 Apr 2020, 09:30
1
Given
(x – y)(x + y) = 15 --> 1
x + y = 5 --> 2
substituting equation 2 in equation 1
--> (x – y)(5) = 15
x – y = 3 --> 3
x + y = 5 --> 2
Adding 2 and 3
2x = 8
x=4 --> 4
Substituting equation 4 in equation 3
4+y=5
y=1 --> 5
from equation 4 and equation 5
x/y = 4/1 =4
Hence, B is the Answer.
(x – y)(x + y) = 15 --> 1
x + y = 5 --> 2
substituting equation 2 in equation 1
--> (x – y)(5) = 15
x – y = 3 --> 3
x + y = 5 --> 2
Adding 2 and 3
2x = 8
x=4 --> 4
Substituting equation 4 in equation 3
4+y=5
y=1 --> 5
from equation 4 and equation 5
x/y = 4/1 =4
Hence, B is the Answer.
gmatclubot
Re: If (x – y)(x + y) = 15 and x + y = 5, then what is the valu [#permalink]
14 Apr 2020, 09:30
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