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:
252 comments Page 18 of 26.
Rajesh said:
1 decade ago
Hi friends, for most of these questions, just understanding the questions is enough and you don't need any formulas.
In the above problem train passes at 45 km/hr so for 1s it will go (45*5/18) = 12.5 m.
And for 30 s it will go 12. 5 * 30 = 375 m.
But we have to reduce trains length (for crossing a pole or person or bridge). So 375-130 = 245 m.
In the above problem train passes at 45 km/hr so for 1s it will go (45*5/18) = 12.5 m.
And for 30 s it will go 12. 5 * 30 = 375 m.
But we have to reduce trains length (for crossing a pole or person or bridge). So 375-130 = 245 m.
Lovepreet kaur said:
1 decade ago
I have solved this problem in another way.
Here am explaining it.
Distance=speed*time;
Length of train = 130m.
Speed = 45 km/hr or 45*1000/3600 m/sec.
Time = 30 sec.
Length = (45*1000/3600)*30 = 375m.
Length of bridge = 375-130 = 245m.
Here am explaining it.
Distance=speed*time;
Length of train = 130m.
Speed = 45 km/hr or 45*1000/3600 m/sec.
Time = 30 sec.
Length = (45*1000/3600)*30 = 375m.
Length of bridge = 375-130 = 245m.
Dileep kumar said:
1 decade ago
Hai friends don't be confuse with considering different formulas, let use single formula to solve these all type of questions, i.e.
Distance = speed*time; OR (D = ST) ;
Let us consider bridge length = x;
Total length (x+130) = (25/2) *30;
x + 130 = 375;
x = 375-130;
x = 245.
Distance = speed*time; OR (D = ST) ;
Let us consider bridge length = x;
Total length (x+130) = (25/2) *30;
x + 130 = 375;
x = 375-130;
x = 245.
P.Deepika said:
1 decade ago
I Had one doubt.,
Crossing means we want to consider as opposite direction as formula (u-v) as (375-130) = 245?
Is This Write Or Wrong, If Any One Please Answer Me.
Crossing means we want to consider as opposite direction as formula (u-v) as (375-130) = 245?
Is This Write Or Wrong, If Any One Please Answer Me.
Dumpati Mahesh said:
1 decade ago
Here we should consider as per the problem that, Train is passing only one time through the bridge. So 130+B.L. Only sanjay.
Thamilarasan said:
1 decade ago
Have any common formulas for easily learning?
Sanjay said:
1 decade ago
B.L. = Bridge Length.
For crossing the bridge distance should be 130+ (B.L) +130.
Then why you are taking 130 + B.L?
For crossing the bridge distance should be 130+ (B.L) +130.
Then why you are taking 130 + B.L?
Sunil Kumar said:
1 decade ago
Let bridge length x m then.
Length of train = 130.
Speed 45*5/18 = 12.5.
Distance=12.5*30 = 375.0-130 = 245.
Length of train = 130.
Speed 45*5/18 = 12.5.
Distance=12.5*30 = 375.0-130 = 245.
Dileep kumar said:
1 decade ago
Distance = speed/time;
Let us bridge length = x say, train travelling distance = 130 m.
The total distance is = x+130;
Speed = 25/2;time = 30sec;
:: x+130 = (25/2) 30;
x = 375-130;
= 245.
Let us bridge length = x say, train travelling distance = 130 m.
The total distance is = x+130;
Speed = 25/2;time = 30sec;
:: x+130 = (25/2) 30;
x = 375-130;
= 245.
Ananth G said:
1 decade ago
@Rohit,
Length=(speed*time).
What you know take left side others stay right side, listen down.
Length
------- = speed {(130+X)/30=25/2,
Time
Than you workout cross multiply method then you get 245m.
Length=(speed*time).
What you know take left side others stay right side, listen down.
Length
------- = speed {(130+X)/30=25/2,
Time
Than you workout cross multiply method then you get 245m.
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