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(x−2)(2+y)=? (1) x·y=6 (2) x+y=5 [#permalink]
 21 Jun 2011, 00:58
Question Stats:
60% (02:14) correct
39% (00:31) wrong based on 0 sessions
(x−2)(2+y)=? (1) x·y=6 (2) x+y=5 Source Master Gmat sample Test Q 20
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Re: x,y and the rest of the band [#permalink]
21 Jun 2011, 01:15
Statement 1: if you substitute for 6/x for y you get 2 values for x which means there is no certain answer
Statement 2: ditto. if you substitute 5-y for x you get (3-y)(2+y), which gives you, y = 3 of y = -2.
I had some trouble working it out and the whole post got messed up (I think I did something wrong using some math signs or something:S), I'll try to do it later.
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Re: x,y and the rest of the band [#permalink]
21 Jun 2011, 01:15
The answer is E. (1) and (2) don't give single specific values for x and y. Combination of (1) and (2) gives a quadratic equation, which can give 2 values of x (or y), which in turn can result in two values of the expression that we're supposed to evaluate. Hence there is no single specific answer for the expression based on data given.
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Re: x,y and the rest of the band [#permalink]
21 Jun 2011, 07:59
shouldnt it b C? From 1 and 2 we can get values of X and y ( 2 equations and 2 variables ) from 1 & 2 -> x = 7/2 , y=3/2 from this we can calculate the value of x−2)(2+y)=?
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Re: x,y and the rest of the band [#permalink]
21 Jun 2011, 08:12
msbinu wrote: shouldnt it b C?
From 1 and 2 we can get values of X and y ( 2 equations and 2 variables )
from 1 & 2 -> x = 7/2 , y=3/2
from this we can calculate the value of x−2)(2+y)=? from 1 & 2 -> x = 7/2 , y=3/2..............?????? this is wrong.. x*y = 6 your values give 21/4
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Re: x,y and the rest of the band [#permalink]
21 Jun 2011, 08:16
sorry .. my bad . .I read x*y as x-y  ..
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Joined: 03 Jun 2010
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Re: x,y and the rest of the band [#permalink]
21 Jun 2011, 08:17
msbinu wrote: shouldnt it b C?
From 1 and 2 we can get values of X and y ( 2 equations and 2 variables )
from 1 & 2 -> x = 7/2 , y=3/2
from this we can calculate the value of x−2)(2+y)=? From 1) and 2) we have answer pairs: (2;3) and (3;2)substitute it and get: 1*4=4or 0*5=0two different answers, (E)
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Re: x,y and the rest of the band [#permalink]
25 Jun 2011, 19:28
1. Not sufficient
different combinations of x , y yields different values.
2 3
6 1
2. Not sufficient
different combinations of x , y yields different values.
1 4
2 3
Together .. Not sufficient
we know that x can be 2 or 3
then y can be 3 or 2.
these two combinations yields different values..
Answer is E.
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Senior Manager
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Re: x,y and the rest of the band [#permalink]
20 Jul 2011, 03:36
Normally, the 2 equation system has 2 set of solution
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Manager
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Re: x,y and the rest of the band [#permalink]
05 Sep 2011, 09:22
Quote: (x−2)(2+y)=?
(1) x·y=6
(2) x+y=5
Source Master Gmat sample Test Q 20 (x-2)(2+y) = xy - 2y + 2x -4 ...............[eq 1] From Statement 1Insert x.y=6 into [eq 1], 6 - 12/x + 2x - 4 = 2x-10 insufficient From Statement 2x+y=5 y=5-x Insert into [eq 1], x(5-x)-2(5-x)+2x-4 = 5x-x^2-10+2x+2x-4 = -x^2+9x-14 insufficient Statement 1 + 2x(5-x)=6 5x-x^2-6=0 (-x-2)(x-3)=0 x=3 or x =2 Insufficient Answer: E Quote: The answer is E. (1) and (2) don't give single specific values for x and y. Combination of (1) and (2) gives a quadratic equation, which can give 2 values of x (or y), which in turn can result in two values of the expression that we're supposed to evaluate. Hence there is no single specific answer for the expression based on data given.
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Re: x,y and the rest of the band
[#permalink]
05 Sep 2011, 09:22
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