Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 3)
3.
The length of the bridge, which a train 130 metres long and travelling at 45 km/hr can cross in 30 seconds, is:
200 m
225 m
245 m
250 m
Answer: Option
Explanation:

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

Time = 30 sec.

Let the length of bridge be x metres.

Then, 130 + x = 25
30 2

2(130 + x) = 750

x = 245 m.

Video Explanation: https://youtu.be/M_d8WufJWKc

Discussion:
247 comments Page 7 of 25.

Pobitro Ghosh said:   8 years ago
Hi,
I solved it differently.
Like,
Total speed= 45*5/18=25/2*30=375,
Actual speed of the train= 375-130=245.
Ans: 245.

Thameem ansari said:   8 years ago
45*5/18=75/6*30=375-130=245m.

Manoj Reddy said:   8 years ago
Nice explanation @Rajesh.

Vichithra said:   8 years ago
@Abd.

I have solution to ur question,

Speed = 45 x (5/18) m/sec = (25/2) m/sec.
Time = 30 sec.
distance = speed x time.
=(25/2)*30.
=750/2.

Multiplication 25 with 30, is 750.

Patel said:   8 years ago
Nice explanation @Rajesh.

Abd said:   8 years ago
How 750? Explain please.

Zainab said:   8 years ago
@Anil Bhadani.

Clear explanation.

Naveen said:   8 years ago
Why you added train length and bridge length?

Sowmiya said:   8 years ago
Nice explanation @Coolburn.

Irene said:   8 years ago
From this formula 2 (130 + x) = 750 ,shouldn't the 2 outside multiple both 130 and x?
I believe it shd be;

160+2x =750,
2x=750-160,
2x=590/2,
x=295m,

2(130+x)=750.


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