UPSC ONLINE ACADEMY

TRAINS SET 4

Q.1 A train passes a pole on the platform in 3sec & the platform in 8sec. If the length of the platform is 120m. Find the length of the train ?
A) 68m
B) 69m
C) 71m
D) 72m
Ans. D
Shortcut:
120/ (8-3) * 3
120/5 * 3
=72m

Q.2 Two trains of length 100m & 80m run on parallel lines of rails. When running in the same direction faster train passes the slower train in 18sec but when they are running in opposite direction with the same speed as earlier they pass each other in 9 sec. Find the speed of each train ?
A) Faster train:15m/sec , Slower train:5m/sec
B) Faster train:5m/sec , Slower train:15m/sec
C) Faster train:12m/sec , Slower train:4m/sec
D) Faster train:4m/sec , Slower train:12m/sec
Ans. A
Shortcut:
Faster train:
Sum of length/2 * sum of time/product of time
i.e (100+80/2) * (18+9 /18*9)
=15m/sec
Slower train:
Sum of length/2 * Difference of time / Product of time
(100+80/2) * (18-9/18*9)
=5m/sec

Q.3 Without stoppage a train covers certain distance at an average speed of 80km/hr but with the stoppages it covers same distance at an average speed of 60 km/hr. How much time per hour does the train stop ?
A) 15 min
B) 16min
C) 17min
D) 18min
Ans. A
Shortcut
Time=Difference in speed/Speed without stoppage
Or 80-60/80
=1/5 hrs
Or 15min

Q.4 At a Railway Office , a passenger was told that a train for Delhi had left 15 min ago but after every 45 min. a train leaves for Delhi. Next train will leave at 8:30 pm. At what time was this information given to the passanger ?

A) 8:05 pm

B) 8:15 pm

C) 7:45 pm

D) 8:00 pm

Ans. D

8:30 – 45 min. + 15 min
= 8:00 pm

Q.5 Running at a speed of 60 km per hour, a train passed through 1.5 km long tunnel in two minutes. What is the length of train ?

A) 1500 m

B) 250 m

C) 500 m

D) 1000 m

Ans. C

Let length of train be 1 metre
Speed of the train = 60 km/hr
= 60 * 1000
=60000 m/hr
Length of tunnel = 1.5 km = 1500 m
Time taken by train = 2 min. = 1/30 hr
Time = Distance / Speed
1/30 = 1+1500/60000
l = 500 m

 

 

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