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OptimusPrep
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We need to understand the meaning of the sentence before we start to solve.girishj wrote:Why is B correct and E wrong?
The westinghouse air brake, first demonstrated successfully in 1868, had been developed to such an extent by 1887 that a train of 50 freight cars traveling at 20 miles per hour could be brought to a standstill in the space of 171 feet, whereas before they required 5 hand breakers over a distance of 1,500 feet for such a train to be stopped.
(a) whereas before they required 5 hand breakers over a distance of 1,500 feet for such a train to be stopped.
(b) whereas previously 5 hand breakers operating over a distance of 1,500 feet had been required to stop such a train.
(c) but before stopping the train required 5 hand breakers operating over a distance of 1,500 feet.
(d) but previously they required 5 hand breakers over a distance of 1,500 feet stopping the train.
(e) but before stopping such a train required 5 hand breakers over a distance of 1,500 feet.
There is a contrast here and "whereas" does that.
Moreover, in option E, before does not properly point to a time frame and this statement is just bad ...
Correct Option: B
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Danny@GMATAcademy
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The meaning in answer choice E veers slightly from the intended meaning of the original sentence.
The original sentence indicates that, in the past, hand brakers were used to stop the train.
Answer E suggests that the hand brakers were just a thing trains needed prior to stopping.
This is related to the time-frame issues. The before in E seems to be modifying the gerund stopping. So the second half of the sentence (what follows the comma-but) has a structure similar to 'before speaking you need to think.' 'before stopping trains need these braker things' does not give the 'in the past' idea from the original.
B makes clear that the hand brakers were used to stop the train ('hand breakers operating...') and it is clear that we are talking about an earlier time-frame (previously doesn't have the ambiguity problems of before, because previously cannot be used as a preposition).
The original sentence indicates that, in the past, hand brakers were used to stop the train.
Answer E suggests that the hand brakers were just a thing trains needed prior to stopping.
This is related to the time-frame issues. The before in E seems to be modifying the gerund stopping. So the second half of the sentence (what follows the comma-but) has a structure similar to 'before speaking you need to think.' 'before stopping trains need these braker things' does not give the 'in the past' idea from the original.
B makes clear that the hand brakers were used to stop the train ('hand breakers operating...') and it is clear that we are talking about an earlier time-frame (previously doesn't have the ambiguity problems of before, because previously cannot be used as a preposition).
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GMATGuruNY
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Only SIMILAR THINGS can be compared.
E: The Westinghouse air brake had been developed by 1887, but before stopping such a train required 5 hand breakers.
Here, but serves to connect the two colored clauses above.
The subject of the red clause is not crystal clear.
It is possible that the subject of required is stopping, implying that the act of STOPPING SUCH A TRAIN required 5 hand breakers.
It is possible that the subject of required is such a train, implying that SUCH A TRAIN required 5 hand breakers before stopping.
Neither subject is similar to the subject of the blue clause (the Westinghouse air brake).
The result is an illogical comparison.
Eliminate E.
OA: The Westinghouse air brake had been developed by 1887, whereas previously 5 hand breakers had been required.
Here, the two subjects in blue are SIMILAR:
Each refers to a MECHANISM used to stop a train.
The result is a logical comparison.
E: The Westinghouse air brake had been developed by 1887, but before stopping such a train required 5 hand breakers.
Here, but serves to connect the two colored clauses above.
The subject of the red clause is not crystal clear.
It is possible that the subject of required is stopping, implying that the act of STOPPING SUCH A TRAIN required 5 hand breakers.
It is possible that the subject of required is such a train, implying that SUCH A TRAIN required 5 hand breakers before stopping.
Neither subject is similar to the subject of the blue clause (the Westinghouse air brake).
The result is an illogical comparison.
Eliminate E.
OA: The Westinghouse air brake had been developed by 1887, whereas previously 5 hand breakers had been required.
Here, the two subjects in blue are SIMILAR:
Each refers to a MECHANISM used to stop a train.
The result is a logical comparison.
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Danny Sir,Danny@GMATAcademy wrote:The meaning in answer choice E veers slightly from the intended meaning of the original sentence.
The original sentence indicates that, in the past, hand brakers were used to stop the train.
Answer E suggests that the hand brakers were just a thing trains needed prior to stopping.
This is related to the time-frame issues. The before in E seems to be modifying the gerund stopping. So the second half of the sentence (what follows the comma-but) has a structure similar to 'before speaking you need to think.' 'before stopping trains need these braker things' does not give the 'in the past' idea from the original.
B makes clear that the hand brakers were used to stop the train ('hand breakers operating...') it is clear that we are talking about an earlier time-frame (previously doesn't have the ambiguity problems of before, because previously cannot be used as a preposition).
I am having a hard time understanding what the sentence seems to imply.
The 1500 feetmentioned in the sentence implies which of the following.
1) The 5 hand brakes are spread over a distance of 1500 feet
2) OR With the help of these 5 hand brakes the train comes to a halt in 1500 feet.
Which of the above is the correct meaning ?
Kindly clear this doubt of mine.
Regards
Teja
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800_or_bust
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Choice (E) is a trainwreck. Pun intended. More seriously, the meaning is ambiguous as some of the others pointed out.girishj wrote:Why is B correct and E wrong?
800 or bust!
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Danny@GMATAcademy
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Hi Teja,Danny Sir,
I am having a hard time understanding what the sentence seems to imply.
The 1500 feetmentioned in the sentence implies which of the following.
1) The 5 hand brakes are spread over a distance of 1500 feet
2) OR With the help of these 5 hand brakes the train comes to a halt in 1500 feet.
Which of the above is the correct meaning ?
Kindly clear this doubt of mine.
Regards
Teja
The ambiguity you point out is one of the reasons A, D and E are not good answer choices. In each of these, we can't tell whether the brakers are operated over a distance of 1500 feet or are spread out over a distance of 1500 feet. It's a good sign that you recognize this subtlte ambiguity.
Answer B makes it clear that the 5 brakers are operating over 1500 feet in order to stop the train. This matches your second option; the train stopped in 1500 feet. And this idea logically completes the comparison with the first half of the sentence (which states that later on airbrakes could bring this type of train to a stop in only 171 feet).
While we're talkng about ambiguity, note as well that A and D contain ambiguous pronouns. There is no clear antecedent for they.
Hope this helps,
Danny
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gui_guimaraes
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Hi @GMATGuruNY Isn't it "stoping" on C and E a dangling modifier? tks!GMATGuruNY wrote: ↑Wed Jul 06, 2016 2:39 amOnly SIMILAR THINGS can be compared.
E: The Westinghouse air brake had been developed by 1887, but before stopping such a train required 5 hand breakers.
Here, but serves to connect the two colored clauses above.
The subject of the red clause is not crystal clear.
It is possible that the subject of required is stopping, implying that the act of STOPPING SUCH A TRAIN required 5 hand breakers.
It is possible that the subject of required is such a train, implying that SUCH A TRAIN required 5 hand breakers before stopping.
Neither subject is similar to the subject of the blue clause (the Westinghouse air brake).
The result is an illogical comparison.
Eliminate E.
OA: The Westinghouse air brake had been developed by 1887, whereas previously 5 hand breakers had been required.
Here, the two subjects in blue are SIMILAR:
Each refers to a MECHANISM used to stop a train.
The result is a logical comparison.
