Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 5)
5.
A train passes a station platform in 36 seconds and a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, what is the length of the platform?
120 m
240 m
300 m
None of these
Answer: Option
Explanation:

Speed = 54 x 5 m/sec = 15 m/sec.
18

Length of the train = (15 x 20)m = 300 m.

Let the length of the platform be x metres.

Then, x + 300 = 15
36

x + 300 = 540

x = 240 m.

Discussion:
279 comments Page 14 of 28.

Anusha said:   3 years ago
Speed = l + b (length of train +platforn).
Speed of train = 54*5/18 = 15.
speed = d/t -----> d = s*t.
d = 15*36-20 (time of train - time of man).
d = 240m.
(18)

Gaurav said:   1 decade ago
Can we do it on this way.

In 36 second train run 36 x 15 = 540 m.
In 20 second train run 20 x 15 = 300 m.

And the length of platform is 540 - 300 = 240 mtr.

Abhishek said:   1 year ago
Train and man cross each other at the same direction so time is (36s-20s) = 16s.
Distance = speed * time.
Speed = 54*5/18=15m/s.
So, distance =15 * 16 =240m.
(142)

Cristianomahesh said:   9 years ago
Hii guys, I think.

Length = speed * time.

We have to find platform length so we have taken the man standing on platform time.

Therefore, length = 15 * 20.

Thiyagu said:   9 years ago
54 * (5/18) = 15m.
x = 36s y = 20s.
x - y = 16s (dist b/w train reach the station - train reach the man).

Now,
15 * 16 = 240m (speed * dist).
Answer = 240m.

Remy said:   2 decades ago
How come (300+x) /15?its not said the man stands at the beginning of platform. If hes somwhere in the middle how come we add the length of the train 300 m ?

Suganthan.m said:   1 decade ago
Hi Guys

speed=15 m/s
A train passes the platform in 36 secs
15*36=540
a man standing on the platform in 20 secs
15*20=300

540-300=240
Ans:240 Am I right

Syed zubair said:   6 years ago
Just subtract the time taken by train to pass a man with the time taken by a train to pass a station i.e 36-20 = 16.

16*15(speed in meters) = 240 meters.

Rahul said:   1 decade ago
Please tell me the reason why we can not calculate lenght of train through 15*36=540 can we calculate lenght of train like this if nt thn tell me reason.

Ramkumar said:   1 decade ago
Speed = 54*(5/18) = 15m/s.

Now time = 36-20 = 16.

Now distance(i.e length) = speed*time.
= 15*16.
= 240m/s.

This is way of correct. Please explain.


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