Quantitative Aptitude Ques 891
Question: A train, 300 m long, passed a man, walking along the line in the same direction at the rate of 3 km/h in 33 s. The speed of the train is
Options:
A) $ 30km/h $
B) $ 32\frac{8}{11}km/h $
C) $ 32km/h $
D) $ 35\frac{8}{11}km/h $
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Answer:
Correct Answer: D
Solution:
- Given, length of train $ =300m $ Let train’s speed be $ x,m/s. $ $ Time=33s $ Man’s speed $ =3km/h=\frac{3\times 5}{18}m/s=\frac{5}{6}m/s $
$ \therefore $ Relative speed = Train’s speed $ - $ Man’s speed $ =x-\frac{5}{6} $ Then, $ x-\frac{5}{6}=\frac{300}{33} $
$ \Rightarrow $ $ \frac{6x-5}{6}=\frac{300}{33}=\frac{100}{11} $
$ \Rightarrow $ $ x=\frac{655}{66}m/s $ $ =\frac{655}{66}\times \frac{18}{5}=35\frac{8}{11}km/h $
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