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.
OA:B
Source:GMATPrep EP2
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The westinghouse air brake, first demonstrated
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they has no antecedent: A and D,thus, are out.( Intended antecedent is train. However, it is singular).
Between the train and such a train, the train is so general that it changes the meaning drastically; C and D are out.
Prep phrase in this position( sub +verb+...noun +prep phrase) can serve the purpose of an adverb or of an adj;Both of these interpretations are illogical.
5 hand breakers are not over a distance of 1500 feet;
They, however, are operating over a distance of 1500 feet (as communicated unambiguously in OA).
Needless to say, in OA, simple past tense wouldn't have been incorrect either( or perhaps would have been a lil better because of an adverb previously).
Between the train and such a train, the train is so general that it changes the meaning drastically; C and D are out.
over a distance of 1,500 feet is a prep phrase.E)but before stopping such a train required 5 hand breakers over a distance of 1,500 feet
Prep phrase in this position( sub +verb+...noun +prep phrase) can serve the purpose of an adverb or of an adj;Both of these interpretations are illogical.
5 hand breakers are not over a distance of 1500 feet;
They, however, are operating over a distance of 1500 feet (as communicated unambiguously in OA).
Needless to say, in OA, simple past tense wouldn't have been incorrect either( or perhaps would have been a lil better because of an adverb previously).
