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X>Y

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Source: — Data Sufficiency |
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X>Y

by November Rain » Tue Oct 20, 2009 8:17 am
Hi
I think the answer is B. I think the best approach is to pick values:
To check if statement 1. is sufficient, try pick X= 10 and Y=2 with a price of 100. You would get 110 when you increase the price by 10 % and then you would have 107,8 when you decrease it by two.

However, if you make X=10 and Y=9,5, you would have a final price of 99,55, so its insufficient.

Concerning statement 2, any X value will always be 1,2 higher than Y (for example if Y is 10%, X is 12%).
And because of difference between X and Y is constant and high, the final price (no matter what its value is) will always be higher than the initial price. So B is sufficient.

Could you please confirm me the OA?
Thanks
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by crackgmat007 » Tue Oct 20, 2009 4:17 pm
Even I got B. OA - E
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by Talkativetree » Tue Oct 20, 2009 8:24 pm
for (2) one interesting idea is could you increase a number by a negative percent? that's just a random pondering. But, just look at two simple examples for (2).

y=1%
y=100%

x=1.2(.01)=1.2%
x=1.2(1.0)=120%

if the original price is 100, then here are the following situations

1.012(100)=101.2
1.2(100)=120.

1% of 101.2=1.012.

101.2-1.012=100.988

for scenario 2,

100% decrease in 120

120-1.0(120)=0
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Re: X>Y

by life is a test » Wed Oct 21, 2009 9:26 am
crackgmat007 wrote:Pls solve.
from what i can understand statement 2 is saying the gap between x and y must be 20%. Since y% has a compounding effect, the outcome will depend on value chosen for x% and the actual number used:

e.g. x=50%, y= 30% starting value = 100 --> 150 --> 105 (ending value) hence ans is yes but if x=100%, y=80%, starting value 100 --> 200 --> 40 then ans is no.

the logic to this question is pretty hazy in my mind also so pls share if you have another take on this - never know which questions will come to haunt us in the actual exam!

thks.
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Re: X>Y

by fruti_yum » Sat Oct 24, 2009 11:41 am
life is a test wrote:
crackgmat007 wrote:Pls solve.
from what i can understand statement 2 is saying the gap between x and y must be 20%. Since y% has a compounding effect, the outcome will depend on value chosen for x% and the actual number used:

e.g. x=50%, y= 30% starting value = 100 --> 150 --> 105 (ending value) hence ans is yes but if x=100%, y=80%, starting value 100 --> 200 --> 40 then ans is no.

the logic to this question is pretty hazy in my mind also so pls share if you have another take on this - never know which questions will come to haunt us in the actual exam!

thks.

Experts pls help!
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by NikolayZ » Sat Oct 24, 2009 4:15 pm
Hey guys!

1) We can't say anything only having x>y, we need to know an extent to which x increased the price and y decreased the price. So insufficient

2) if x=1,2y, we need to know does x*y> or <1.
Substituting 1,2y*y=1,2y^2, let's assume that the product must be >1, to solve this DS problem.
1,2y^2>1, y^2>10/12, y>sqrt(10/12). I believe that if y=0,99 , y indeed would be greater than sqrt(10/12), but it might be less than that figure. So we still have this question unanswered => insufficient.
Is it alright with this approach or am i missing smth ?
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