"I never think of the future. It comes soon enough."
- Albert Einstein
29.
A train travelling at 48 kmph completely crosses another train having half its length and travelling in opposite direction at 42 kmph, in 12 seconds. It also passes a railway platform in 45 seconds. The length of the platform is
After found the length of the first train then it will come to know about the length of 2nd train because (x/2).
When we find the length of the platform. Why did we use the first train length?
Vineet said:
(Sat, Dec 11, 2010 07:04:01 PM)
The answer isn't correct. It should be 600m.
Proof: If you go by other way taking length of the platform as 400m and time as 45 seconds.
Then the speed of the train would come as: (400/45)*(18/5)=32kmph(which isn't true)
Sowjanya said:
(Wed, Jan 26, 2011 03:35:21 AM)
Can anybody explain this problem clearly ?
Nakul Gowda said:
(Wed, Jan 26, 2011 01:23:57 PM)
@Vineet:
You are wrong buddy,,..you have to add train's length as well.
So it'd be 400+200=600/45*18/5 = 48 kmph.
Priya said:
(Sun, May 8, 2011 12:23:48 AM)
I think answer for length of the platform is 200m.
(400+y) /45=48*5/18.
Solving this we get y=200m.
Vinay said:
(Thu, Aug 18, 2011 11:04:39 AM)
According to the problem,
First let us take length of the first train as "x"
So the length of the second train is half of the second train so it is half of x
So the total length is "(3/2)x"
and given that the two trains are travelling in opposite directions so that their relative speed = (48+42)km/hr.
now convert into m/s so it is 90*(5/18) =25 m/s.
from basic rule s = d /t;
25 m/s = ((3/2)x)/ 12 sec
by solving it we get x = 200m
and given that time required to pass platform is 45 sec
and length of platform = z
48 * (5/18) = (200+z) m/ 45 sec
by solving it we get finally 400 m
Syndhya said:
(Thu, Jan 26, 2012 10:34:25 AM)
Could anybody explain clearly. Please. I can't understand. Explain in a simple manner please.
600 + 3y = 1800