Unplugged Practice Test: Logical Reasoning Set 3, Question 5 (Fill in the Blank)
Taking the test? Finish it first. This page shows the answer.
- Fill in the Blank questions ask you to finish the argument. The blank is usually its conclusion.
- Read the words just before the blank. If they signal a conclusion (so, hence, it follows that), pick the choice the premises already prove. Skip anything that says more than they do.
- Every question on this test is original, written to the same logical skeletons as real questions, and Steve checked every one himself before release.
The question
Clumps of foam torn loose at the base of the Callen falls are carried 200 meters downstream to the pool below the bend. Clumps of the same size sitting in a still eddy break apart in well under 20 seconds. A clump swept the full 200 meters by the current takes roughly 3 minutes to make the trip. If clumps moving swiftly in the current broke apart as fast as clumps in a still eddy do, we would expect only about one-twentieth as many clumps to arrive at the bend as observers actually count. Apparently, clumps of foam moving swiftly in the current ______.
5. Which one of the following most logically completes the argument?
- (A)take longer to reach the bend than has been thought
- (B)are difficult to spot by the counting methods now in use
- (C)are far fewer in number than has been believed
- (D)are probably not torn loose at the falls at all
- (E)hold together longer than clumps that sit nearly still
EWhy (E) is correct
(E) is what the numbers force. If clumps moving swiftly in the current broke apart as fast as clumps in a still eddy, only about one-twentieth as many would reach the pool below the bend as actually arrive there. Since roughly 20 times that number show up, the swiftly moving clumps must be surviving longer than the still ones do, holding together rather than falling apart at the eddy's rate.
Why the other answers are wrong
AWhy (A) is wrong
(A) taking longer to reach the bend doesn't explain why so many more clumps arrive intact, and it sits oddly with clumps that are described as moving swiftly.
BWhy (B) is wrong
(B) being hard to spot by current counting methods would mean fewer clumps get counted, the wrong direction when the puzzle is an unexplained surplus.
CWhy (C) is wrong
(C) fewer clumps than believed would mean fewer arrivals, not more.
DWhy (D) is wrong
(D) that clumps aren't torn loose at the falls at all contradicts the stimulus, which states outright that clumps are torn loose there.
Common questions
What type of question is this?
Fill in the Blank. Fill in the Blank questions ask you to finish the argument. The blank is usually its conclusion.
How do I get better at Fill in the Blank questions?
Read the words just before the blank. If they signal a conclusion (so, hence, it follows that), pick the choice the premises already prove. Skip anything that says more than they do. The free LSAT cheat sheet lists the wrong-answer patterns to watch for on every type.
