If [x] denotes....

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by GMATGuruNY » Mon Feb 28, 2011 3:06 pm
ithamarsorek wrote:If [x] denotes the greatest integer less than of equal to x, is [x] = 0 ?

1) 5x + 1 = 3 + 2x

2) 0 < x < 1



*St 1 gives me X so I know its sufficient. But I couldn't figure out the rest.

Thx
Statement 1: 5x + 1 = 3 + 2x
One variable, one linear equation.
Sufficient information to solve for x.

Statement 2: 0 < x < 1
[positive fraction] = greatest integer less than or equal to the positive fraction = 0. The greatest integer less than any positive fraction is 0.
To illustrate:
[1/2] = greatest integer less than or equal to 1/2 = 0.
[3/4] = greatest integer less than or equal to 3/4 = 0.
[1/100,000] = greatest integer less than or equal to 1/100,000 = 0.
Sufficient.

The correct answer is D.
Last edited by GMATGuruNY on Mon Feb 28, 2011 3:16 pm, edited 1 time in total.
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by ithamarsorek » Mon Feb 28, 2011 3:13 pm
Just for clarification:

[x] = positive fraction x
[z] = positive fraction z
etc...

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by GMATGuruNY » Mon Feb 28, 2011 3:20 pm
ithamarsorek wrote:Just for clarification:

[x] = positive fraction x
[z] = positive fraction z
etc...
x = positive fraction, [x] = the greatest integer less than x. Thus, [x] = 0.
z = positive fraction, [z] = the greatest integer less than z. Thus, [z] = 0.
To illustrate why statement 2 is sufficient, I've added some concrete examples to my original post.
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