Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 8)

Problems on Trains

A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long?

40 sec

42 sec

45 sec

48 sec

Answer: Option

Explanation:

Formula for converting from km/hr to m/s: X km/hr =		X x	5		m/s.
			18

Therefore, Speed =		45 x	5	m/sec	=	25	m/sec.
			18			2

Total distance to be covered = (360 + 140) m = 500 m.

Formula for finding Time =		Distance
		Speed

Required time =		500 x 2	sec	= 40 sec.
		25

Discussion:

78 comments Page 2 of 8.

Shubham Jain said: 6 years ago

How come 25/2?

(1)

Nibha said: 6 years ago

Why 140m is added?

(1)

Rohan said: 6 years ago

Why we have to add the length of the train?

Sai said: 6 years ago

450mts ----> 36sec.
500mts ---> 40sec.

(1)

Anush said: 6 years ago

Why we are adding the train length with bridge length?

(1)

Prasad kapal said: 7 years ago

But we added 500 with 140.

Gurwinder singh said: 7 years ago

Why (x*5/18) mps?

ANIL said: 7 years ago

Given,

length of the train =360m,
speed of train =45km/h,
length of the bridge =140m,
time =T.

Now convert 45km/h=45*5/18=225/18m/s.
Total length=360m+140m=500m.
We know speed =distance/time.
=> 225/18=500/T.
=> T=500*18/225.
=> T=40s.

Lavi chaudhary said: 7 years ago

@All.

First of all, 360*5/18=1800/18=100 and finally 140-100=40 ans.

Sarang said: 7 years ago

Distance = speed *time.
360+140=45*5/18*time,
500=5*5*/2*time,
500=25/2*time,
500=12.5*time,
500/12.5=time,
Time = 40 second.

Post your comments here:

Quick links

Quantitative Aptitude

Verbal (English)

Reasoning

Programming

Interview

Placement Papers

Aptitude - Problems on Trains - Discussion

Current Affairs

Interview Questions

Group Discussions