CR: In 1980, 13 percent of the Arbican population moved

[direstraits007]

In 1980, 13 percent of the Arbican population moved from urban areas to suburban areas. This percentage steadily declined, until, in 1990, it reached 3 percent.
If the statements above are true, all of the following statements concerning Arbicans between 1980 and 1990 could also be true EXCEPT:
(A) The number of Arbicans moving from suburban areas to urban areas also
decreased.
(B) The Arbican population increased, and so did the number of Arbicans moving from urban to suburban areas.
(C) The Arbican population decreased, and so did the number of Arbicans moving from urban to suburban areas.
(D) The Arbican population decreased, and the number of Arbicans moving from urban to suburban areas remained the same.
(E) The Arbican population increased, and the number of Arbicans moving from urban to suburban areas remained the same.

OA: D.

source: Kaplan CR tests

Can someone explain why A is wrong. In the stimulus the percentage of people who moved from urban areas to suburban areas is given, but in option A, opposite is stated, which we don't know either it is right or wrong. So, answer shouldn't be A ?

[RonPurewal]

but in option A, opposite is stated,

my first thought is that this problem looks much more like something you'd see on the lsat than something you'd see on the gmat ... but here goes.

i see where you're coming from with this "opposite" claim, but it doesn't have merit. the number of people moving from urban to suburban areas has NOTHING WHATSOEVER to do with the number of people moving from suburban to urban areas. they are two completely unrelated percentages; the ONLY criterion they must satisfy is that (assuming people don't move multiple times) they can't add up to more than 100%.

consider the extreme case in which there is flight from the cities, because of crime, and NOBODY moves TO the cities from the suburbs. then the % referred to in (a) would just be 0% the whole time.

this % could also do just about anything else.

--

analogy:

let's say you get data from some surgical clinic about the % of local men who are having sex changes to transform themselves into women. now, let's say that this % is decreasing.
does this indicate anything, at all, about the % of local women who are having the opposite sex change?
no, of course it doesn't.

same thing here.