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Prac Exam Number Line

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Prac Exam Number Line

by fangtray » Sun Apr 22, 2012 4:26 am
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

OA is A.

but why does A work? If 6 is halfway b/t x and Y, x could = 5 and y = 7 or x = 4 and y = 8....how does A work? what am i not understanding?
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Source: — Data Sufficiency |
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by aneesh.kg » Sun Apr 22, 2012 5:12 am
If x and y are two numbers, then
The average of the two numbers, A = (x + y)/2
or x + y = 2A
So, the questions is asking us the value of 2A, or twice the average.

Statement (1) says that 6 is midway between x and y, which means that A = 6. So, x + y = 2*6 = 12
So, Statement (1) is SUFFICIENT.

So, when you're trying out numbers, no matter which numbers you try (keeping 6 midway) the value of x + y will not change. Interesting, isn't it?

Mark the numbers on the Number Line to understand better.
Aneesh Bangia
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by fangtray » Sun Apr 22, 2012 7:12 am
aneesh.kg wrote:If x and y are two numbers, then
The average of the two numbers, A = (x + y)/2
or x + y = 2A
So, the questions is asking us the value of 2A, or twice the average.

Statement (1) says that 6 is midway between x and y, which means that A = 6. So, x + y = 2*6 = 12
So, Statement (1) is SUFFICIENT.

So, when you're trying out numbers, no matter which numbers you try (keeping 6 midway) the value of x + y will not change. Interesting, isn't it?

Mark the numbers on the Number Line to understand better.
6 is midway between 5 and 7. 6 is also midway between 4 and 8. 6 is also midway between 3 and 9.

oh god all these = 12. why didn't i see that. wow. haha
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