12
Q:

Two trains of equal length , running in opposite directions , pass a pole in 18 and 12 seconds. The trains will cross each other in 

A) 14.4 sec B) 15.5 sec
C) 18.8 sec D) 20.2 sec

Answer:   A) 14.4 sec

Explanation:

Let the length of the train be L metres

Speed of first train = \inline \frac{3600}{18}\times L m/hour

Speed of secxond train = \inline \frac{3600}{12}\times L m/hour

When running in opposite directions, relative speed = 200 L + 300 L m/hour

Distance to be covered = L + L = 2L metre

Time taken = \inline \frac{2L}{500L}\times 3600 sec

                 =14.4 sec

Q:

A train covers a distance between station A and station B in 45 min.If the speed of the train is reduced by 5 km/hr,then the same distance is covered in 48 min.what is the distance between the stations A and B ?

A) 80 kms B) 60 kms
C) 45 kms D) 32 kms
 
Answer & Explanation Answer: B) 60 kms

Explanation:

Let 'd' be the distance and 's' be the speed and 't' be the time
d=sxt
45 mins = 3/4 hr and 48 mins = 4/5 hr
As distance is same in both cases;
s(3/4) = (s-5)(4/5)
3s/4 = (4s-20)/5
15s = 16s-80
s = 80 km.
=> d = 80 x 3/4 = 60 kms.

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1 11
Q:

A train for Fathehpur leaves for every 2 hrs 30 min from Agra station. An announcement was made that train left 37 mins ago and next train comes at 17:00hrs. At what time was the announcement made ? 

A) 15:07 hrs B) 15:20 hrs
C) 15:05 hrs D) 15:00 hrs
 
Answer & Explanation Answer: A) 15:07 hrs

Explanation:

Next train comes at 17:00 hrs.
So, last train will be = 17:00hrs - 2:30hrs
= 14:30hrs
Announcement made after 37 min of the last train.
S0, 14:30hrs + 00:37 min
= 15:07 hrs.

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1 82
Q:

A train moving at 2/3 rd of its normal speed reaches its destination 20 minutes late. Find the normal time taken ?

A) 4/3 hrs B) 2/3 hrs
C) 3/2 hrs D) 1/4 hrs
 
Answer & Explanation Answer: B) 2/3 hrs

Explanation:

Let the original speed and time is S and T
then distance = S x T
Now the speed changes to 2/3S and T is T+20
As the distance is same
S x T = 2/3Sx(T+20)
solving this we get t = 40 minutes
=40/60 = 2/3 hour

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1 24
Q:

Train K crosses a stationary Train L in 50 seconds and a pole in 20 seconds with the same speed. The length of the Train K is 240 meters. What is the length of stationary Train L ?

A) 60 mts B) 120 mts
C) 240 mts D) 360 mts
 
Answer & Explanation Answer: D) 360 mts

Explanation:

Speed of the Train K is given by s = d/t = 240/20 = 12 m/s
Distance covered by Train K in 50 seconds = 12 x 50 = 600 mts.
But it crosses Train L in 50 seconds
Therefore, the length of the Train L is = 600 - 240 = 360 mts.

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1 53
Q:

An express train takes 4 seconds to enter tunnel which is 1 km long. If it is traveling at 108 km an hour, how long will it take to pass completely through the tunnel ?

A) 33 sec B) 37.33 sec
C) 36.43 sec D) 32 sec
 
Answer & Explanation Answer: B) 37.33 sec

Explanation:

Speed = 108 km/hr
enter a tunnel,, means that the train covers a distance equal to its own length
so (108 x 5/18) = x/4 where x= length of train
hence x = 120 mtrs
to pass completely train has to travel a distance = (x + tunnel length) that is 1120 mtrs.
so (1120/t) = (108x5/18)
t = 37.33 sec

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