Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 19)
19.
A train speeds past a pole in 15 seconds and a platform 100 m long in 25 seconds. Its length is:
Answer: Option
Explanation:
Let the length of the train be x metres and its speed by y m/sec.
| Then, | x | = 15  y = |
x | . |
| y | 15 |
 |
x + 100 | = | x |
| 25 | 15 |
15(x + 100) = 25x
15x + 1500 = 25x
1500 = 10x
x = 150 m.
Discussion:
55 comments Page 2 of 6.
Sanjana said:
6 years ago
Good explanation.
Sia Siam Changsan said:
6 years ago
Let x meter be the length of the train.
We have, speed = distance/time.
S=x/15 ( to pole),
Again, s=d/t,
x/15= x+100/25(to platform),
x=150m.
We have, speed = distance/time.
S=x/15 ( to pole),
Again, s=d/t,
x/15= x+100/25(to platform),
x=150m.
(3)
Zeeshan said:
6 years ago
In very simple form:
First calculate the speed relative to platform S=D/T.
S= 100/(25-15).
S= 10m/s.
Now as S = D/T so D= S*T.
D = 10*15= 150m which is relative to Pole.
Or
D= 10*25= 250 which is relative to platform so subtract length of Platform D= 250- 100= 150m.
First calculate the speed relative to platform S=D/T.
S= 100/(25-15).
S= 10m/s.
Now as S = D/T so D= S*T.
D = 10*15= 150m which is relative to Pole.
Or
D= 10*25= 250 which is relative to platform so subtract length of Platform D= 250- 100= 150m.
(11)
Arjun said:
6 years ago
Let x be the length of train.
Therefore speed of train = x/15 m/sec.
x+100 = (x/15) m/sec * 25 sec.
3x+300 = 5x.
x = 300/2 =150 m.
Therefore speed of train = x/15 m/sec.
x+100 = (x/15) m/sec * 25 sec.
3x+300 = 5x.
x = 300/2 =150 m.
Mr.N.P. said:
7 years ago
Time Difference of Platform and Pole = 25-15= 10s.
Platform is 100m long.
speed of Train is = (D/T)=(100/10) =10m/s.
Length of pole(Train) = S * T = 10 * 15 = 150m.
Platform is 100m long.
speed of Train is = (D/T)=(100/10) =10m/s.
Length of pole(Train) = S * T = 10 * 15 = 150m.
(1)
Rosy said:
7 years ago
Please cam someone explains me again?
Ravanan said:
8 years ago
Consider, train length is x now we find out the speed s=d/t here train length is d so s=x/15
x/15=(100+x)/25,
25x=(100+x)*15,
25x=1500+15x,
25x-15x=1500,
10x=1500,
x=1500/10,
x=150m.
x/15=(100+x)/25,
25x=(100+x)*15,
25x=1500+15x,
25x-15x=1500,
10x=1500,
x=1500/10,
x=150m.
(1)
Vaibhav said said:
8 years ago
I can't unable to understand it, please explain.
SANTOSH said:
8 years ago
Can we calculate the speed of the train by the length of platform and time taken by train to cross the platform?
Sangita said:
8 years ago
Why x multiply with 100 and exactly which formula is used here? Please, clearly explain this.
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