Free LSAT Practice Question

Question 1 of 1
ID: LSAT-LR-136
Section: Logical Reasoning
Topic: Weaken the Argument
Difficulty level: Medium

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Reservoir engineer: Less silt reaches the Larne now than before, the largest feeder having been diverted the year before we first opened the low-level gates in the spring flood. Our figures are shares: of the silt that does arrive, the fraction that settles and stays. That fraction has fallen every year since. Flushing is doing at least some of the work of holding off the loss of capacity.

Which one of the following, if true, most weakens the engineer's argument?

ASince the feeder was diverted, the tonnage of silt arriving at the Larne each year has fallen by well over a third, and it goes on falling year by year.

BIn the two springs too weak for the gates to be opened, a higher fraction of the arriving silt settled and stayed than in any flushed spring.

CSilt that consolidated on the bed before the gates were opened will not be shifted by any flushing regime.

DThe silt now reaching the Larne is far finer than what the diverted feeder brought down, and silt that fine leaves through the ordinary outflow instead of settling on the bed.

EEach spring flush sends downstream water the reservoir would otherwise have held into summer, and in two dry years the works has bought water in.

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