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#21 - The amount of electricity consumed in Millville on

LSAT2018
LSAT Master
 
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I understand why A is parallel to the stimulus but I would just like to clarify whether there is valid or invalid reasoning here. In stating that A is directly proportional to B, would they be interchangeable, like working either way? So would it be acceptable to say B increased, A would increase.


Thanks in advance!
Adam Tyson
PowerScore Staff
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Yes, LSAT2018, if two things are directly proportional then you can say that as either one of them increased, so did the other, and as either of them decreased, so did the other. If you accept the claim of direct proportion, then you can use changes in either one to prove changes in the other. That concept comes up now and then on the test, so it's good to be familiar with it, and also with indirect or inverse proportions, where they move in opposite directions.
Adam M. Tyson
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