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If x and y are points on the number line, what is the value [#permalink ]
17 Nov 2007, 11:26

Question Stats:

50% (02:39) correct

50% (00:33) wrong

based on 3 sessions
If x and y are points on the number line, what is the value of x + y?
(1) 6 is halfway between x and y
(2) y = 2x

VP

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Re: DS: x and y are points on the number line [#permalink ]
17 Nov 2007, 11:33

gluon wrote:

If x and y are points on the number line, what is the value of x + y? (1) 6 is halfway between x and y (2) y = 2x

1. x = 3 y=9 or x=0 y=12 thus not suff. (x.................6..................y)

2. y=2x, x=3 y=6 or x=4 y=8. not suff.

combined 1&2

x=4 y=8 thus x+y=12

C

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x+y = ?

statement 1
Lets assume x=3 and y=9 or x=2 and y=10

insufficient

statement 2
y=2x

2x+x = 3x

insufficient

both statements
3x/2 = 6

3x = 12

x = 4

4,6,8 ---> one solution ---> 4+8 = 12

the answer is (C)

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Re: DS: x and y are points on the number line [#permalink ]
17 Nov 2007, 12:13

[quote="gluon"]If x and y are points on the number line, what is the value of x + y?
(1) 6 is halfway between x and y
(2) y = 2x[/quote]
I think it should be A.
If 6 is halfway, it means that X + Y / 2 = 6. means X + Y = 12
we can test it
x = 3 , means y = 9 x+y=12
x = -12, means y= 24 , again x+y =12

Director

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I think it is A.
Killer, Statement A is suff. Look what you said:
statement 1
Lets assume x=3 and y=9 or x=2 and y=10
insufficient
3 + 9 =12
and
2+10 = 12
A tells us it will always equal 12.
B is insuff alone.
Answer should be A.

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Re: DS: x and y are points on the number line [#permalink ]
17 Nov 2007, 15:25

gluon wrote:

If x and y are points on the number line, what is the value of x + y? (1) 6 is halfway between x and y (2) y = 2x

A

If 6 is half way between , then 6 has to be average of two numbers

so (x+y)/2 = 6 => x+y = 12

2 ) is redundant info..

Director

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uh oh! could the great killersquirell be wrong!
I can feel myself growing stronger!

VP

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hmm, the conclusion i made based on stat1 has already told that x+y=12. that's "nicely" paying attention to details
thanks guys. sorry gluon!

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I made the same mistake as Ravshonbek and KS

We tried to find values of x and y separately instead of (x + y)

The OA is indeed A.

So KS does make mistakes sometimes

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Yes , that's why he will never score 800, only 790

VP

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This is definitely going into my

error log .

Nice catch yashchenko !