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# DS : OG11-Q91

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Intern
Joined: 31 Jul 2008
Posts: 31

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27 Aug 2008, 00:23
Hi guys,This is OG-11, DS Q#91

Que: By what percent did the median household income in country Y decrease from 1970 to 1980:
I : In 1970 the median household income in Country Y was 2/3 of the median household income in COuntry X.

II : In 1980 the median household income in Country Y was 1/2 of the median household income in COuntry X.

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My solution:

1970 : Y = 2X/3
1980 : Y = X/2

%ge decrease = [(X/2-2X/3)/(2X/3)]*100
= 25% decrease.

Can anyone please tell me whats wrong here?becuase OA is NOT C.

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Manager
Joined: 14 Jun 2008
Posts: 162

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27 Aug 2008, 00:39
you are assuming that the median income in Country X has not changed
re writing you solution
1970 : Y_1 = 2 X_1 / 3 where X_1 is median income in 1970 in country X
1970 : Y_2 = 2 X_2 / 3 where X_2 is median income in 1980 in country X

now u can see unless u know the increase from X_1 to X_2 cannot say what Y_1 to Y_2 is

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Re: DS : OG11-Q91   [#permalink] 27 Aug 2008, 00:39
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