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:
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 19 of 25.
Zainab said:
8 years ago
@Anil Bhadani.
Clear explanation.
Clear explanation.
Abd said:
8 years ago
How 750? Explain please.
Patel 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.
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.
Manoj Reddy said:
8 years ago
Nice explanation @Rajesh.
Thameem ansari said:
8 years ago
45*5/18=75/6*30=375-130=245m.
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.
I solved it differently.
Like,
Total speed= 45*5/18=25/2*30=375,
Actual speed of the train= 375-130=245.
Ans: 245.
DURAI said:
8 years ago
@Rahul.
Your explanation is clear my doubt thank you.
Your explanation is clear my doubt thank you.
Syam said:
7 years ago
Length of the train l1 = 130m;
Speed s = 45kmph;
time t = 30 sec ;
length of the bridge l2 = ?
Here total distance D= (length of the train + length of the bridge)
so d=l1+l2;
we know the formula of distance (d)=speed(s)*time(t);
but the speed in kmph we have to convert into mph so speed (s) = 45*(5/18)=25/2;
then d=s*t;
then substitute all the values in it.
(l1+l2)=(25/2)*30;
we know the l1 value l1=130m;
(130+l2)=(25*15)
(130+l2)=375
then l2 =375-130
length of the bridge is l2=245;
Speed s = 45kmph;
time t = 30 sec ;
length of the bridge l2 = ?
Here total distance D= (length of the train + length of the bridge)
so d=l1+l2;
we know the formula of distance (d)=speed(s)*time(t);
but the speed in kmph we have to convert into mph so speed (s) = 45*(5/18)=25/2;
then d=s*t;
then substitute all the values in it.
(l1+l2)=(25/2)*30;
we know the l1 value l1=130m;
(130+l2)=(25*15)
(130+l2)=375
then l2 =375-130
length of the bridge is l2=245;
Kuma said:
7 years ago
Speed=Distance/Time.
45*5/18=Distance/30,
375= Distance,
Length= 375-130=245.
45*5/18=Distance/30,
375= Distance,
Length= 375-130=245.
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