og ds 151

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og ds 151

by resilient » Sat Feb 09, 2008 6:57 pm
if x and y are positive , is the ratio of x to y greater than 3?

1. x is 2 more than 3 times y.

2. the ratio of 2x to 3y is greater than 2.

original question i translated to x/y>3 and simplified to x>3y. so the question really is : x>3y?

statement 1 translated to x=3y+2
statement 2 translated to 2x/3y>2 which translates to 2x>6y/2 which simplifies to x>3y.

In testing numbers statement 1 seems sufficient when testin x as 8 and y as 2 but when you tet y as 100 and consequent x as 302 they actually equal eachother and therefore I ruled out statement A and chose B.


QA is C but where did I go wrong.






qa is c ..i chose b
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by simplyjat » Sat Feb 09, 2008 8:19 pm
1. You need more concentration... OA is D not C...

2. You can't convert x/y > 0 to x >.3y until and unless you know the sign of y.
Enginpasa1 wrote:100 and consequent x as 302 they actually equal each other
How do you call them equal? You need to take elementary school maths classes again if you are saying 302 = 300

And why do you need number substitution at all...
Forget about 100, even if y is googol, x/y will still be greater than 3...
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by rapidfire09 » Fri Feb 15, 2008 11:40 am
1st statement x= 3y + 2
=> x - 2 = 3y
=> x/y - 2/y = 3
=> x/y = 3 + 2/y

Now if y is positive then 2/y has to be positive and hance x/y has to be greater than 3.

statement 1 is sufficient.

Now let's take 2nd statement 2x/3y > 2
=> (x/y)(2/3) > 2
=> x/y > 2 (3/2)
=> x/y > 3
Hence statement 2 is sufficient by it self.

Answer is D.

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positive restraints to the answers

by resilient » Sun Feb 17, 2008 12:02 am
I must have looked at the wrong answer choice.

THe the question explains that the a and b are both positive so yes the terms can be translated into my translations..
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stll lost rapidfire

by resilient » Sun Feb 17, 2008 12:10 am
i am trying to get this but I need to plug in numbers.. i think there is an easier way to do this but still lost
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