SATHEE: Quantitative Aptitude Ques 1085

Quantitative Aptitude Ques 1085

Question: Train A travelling at 63 km/h can cross a 199.5 m long platform in 21 s. How much time would train A take to completely cross (from the moment they meet) train B, 257 m long and travelling at 54 km/h in opposite direction in which train A is travelling? [RRB (Officer Assistant) 2015]

Options:

A) 16 s

B) 18 s

C) 12 s

D) 13.07 s

E) 10 s

Show Answer

Answer:

Correct Answer: D

Solution:

[d] Speed of train A = 63 km/h $ =63\times \frac{5}{18}=\frac{7}{2}\times 5=\frac{35}{2}m/s $ Length of platform = 199.5 m Let length of train A = x m Train A take 21 s to cross the platform So, $ \frac{x+199.5}{\frac{35}{2}}=21 $

$ \Rightarrow $ $ 2x+399=21\times 35 $

$ \Rightarrow $ $ 2x=735-399 $

$ \Rightarrow $ $ 2x=366 $
$ \Rightarrow $ $ x=168 $ Length of train $ A=168,m $ Length of train $ B=257,m $ Speed of train $ B=54\times \frac{5}{18}=15m/s $ Since, the trains are in opposite direction. Therefore, time to cross each other $ =\frac{length,of,(TrainA+TrainB)}{Relative,speed,of,train,(A+B)} $ $ =\frac{168+257}{( \frac{35}{2}+15 )}=\frac{425\times 2}{35+30}=\frac{850}{65}=13.076 $ Therefore, time taken by train A to cross train $ B=13.07,s. $

Quantitative Aptitude Ques 1084

Quantitative Aptitude Ques 1086

Quantitative Aptitude Ques 1085

Question: Train A travelling at 63 km/h can cross a 199.5 m long platform in 21 s. How much time would train A take to completely cross (from the moment they meet) train B, 257 m long and travelling at 54 km/h in opposite direction in which train A is travelling? [RRB (Officer Assistant) 2015]

Options:

Answer:

Solution:

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