Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 27)
27.
A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph and passes them completely in 9 and 10 seconds respectively. The length of the train is:
Answer: Option
Explanation:
| 2 kmph = |  |
2 x | 5 |  |
m/sec = | 5 | m/sec. |
| 18 | 9 |
| 4 kmph = | |
4 x | 5 | |
m/sec = | 10 | m/sec. |
| 18 | 9 |
Let the length of the train be x metres and its speed by y m/sec.
| Then, |  |
x |  |
= 9 and | |
x | |
= 10. |
|
|
9y - 5 = x and 10(9y - 10) = 9x
9y - x = 5 and 90y - 9x = 100.
On solving, we get: x = 50.
Length of the train is 50 m.
Discussion:
106 comments Page 3 of 11.
Ronie said:
7 years ago
@Vamc.
You need to convert the 2kmph and 4kmph to mps. So on converting it gives 5/9 m/s and 10/9m/s.
According to the formula for the same direction movement: (speed of train -speed of man).
As the speed of man is slow.
You need to convert the 2kmph and 4kmph to mps. So on converting it gives 5/9 m/s and 10/9m/s.
According to the formula for the same direction movement: (speed of train -speed of man).
As the speed of man is slow.
Jugnu said:
8 years ago
Distance=(speed-5/9)*9 and distance=(speed-10/9)*10.
If distance is x then (speed-5/9)*9=(speed-10/9)*10.
Let speed be y.
(y-5/9) * 9 = (y-10/9) * 10.
9y-45 = 10y-100/9.
y = 305/9.
Then distance will be 300.
Am I right.
If distance is x then (speed-5/9)*9=(speed-10/9)*10.
Let speed be y.
(y-5/9) * 9 = (y-10/9) * 10.
9y-45 = 10y-100/9.
y = 305/9.
Then distance will be 300.
Am I right.
Mojib Rahman said:
9 years ago
Let, Speed =X kmph.
Length = d km.
Again, relative speed Of A = x-2 & B=x-4.
9/3600 = d/x-2 (1).
10/3600 = d/x-4 (2).
We get, X=22.
From eq(1),
9/3600 = d/20.
d = 180/3600 = 1/20km = 1000/20m = 50m.
Length = d km.
Again, relative speed Of A = x-2 & B=x-4.
9/3600 = d/x-2 (1).
10/3600 = d/x-4 (2).
We get, X=22.
From eq(1),
9/3600 = d/20.
d = 180/3600 = 1/20km = 1000/20m = 50m.
Ramya said:
6 years ago
Relative speed respect to 1 person and train= (x-2).
Relative speed respect to 2nd person and train= (x-4).
Dist. = speed * time.
9(x-2) = 10(x-4).
x = 22.
So, 22-2 = dist/9.
dist = 180*(5/18).
> 50.
Relative speed respect to 2nd person and train= (x-4).
Dist. = speed * time.
9(x-2) = 10(x-4).
x = 22.
So, 22-2 = dist/9.
dist = 180*(5/18).
> 50.
Alpesh jiwane said:
1 decade ago
What is the speed of a train if it overtakes two persons who are walking in the same direction at the rate of a m/s, (a+1) m/s, and passes them completely in b second and (b+1) seconds respectively?
Nayana said:
1 decade ago
Here after solving 10=x/9y-10 will give rise 90y-100=x.
After solving 9=x/9y-5 we are getting 9y-5=x. here why we they are not multiplying 9 with (9y-5).
Please any tell the answer for this.
After solving 9=x/9y-5 we are getting 9y-5=x. here why we they are not multiplying 9 with (9y-5).
Please any tell the answer for this.
Nitesh Mittal said:
7 years ago
2*9=18
4*10=40
10-9=1
Speed of train =(40-18)/1
Speed of train =22 km/hr
Now,
Length of train = (22-2) *(5/18) *9.
= 20*5/2,
= 50 mins.
4*10=40
10-9=1
Speed of train =(40-18)/1
Speed of train =22 km/hr
Now,
Length of train = (22-2) *(5/18) *9.
= 20*5/2,
= 50 mins.
Naresh said:
8 years ago
The right answer is 50m. You will get the speed of the train is 22 kmph.So, Length is.
22-2 (velocity of first person) = length/9.
20*5/18 = length/9.
So, the length of the train is 50 m.
22-2 (velocity of first person) = length/9.
20*5/18 = length/9.
So, the length of the train is 50 m.
Prachi rokade said:
2 years ago
Can solve this way: Same direction a person walk so the subtraction of speed i.e 4-2 = 2kmph.
And (2*5/18)m/s =5/9.
Now the time is 9 and 10-sec addition of two is 90.
So, 90 * 5/9 = 50.
And (2*5/18)m/s =5/9.
Now the time is 9 and 10-sec addition of two is 90.
So, 90 * 5/9 = 50.
(34)
Partha said:
4 years ago
90y - 5 = x, 90y - 9x = 100.
Putting the value of x in 2nd so 90y - 81y + 45 = 100,
So after solving, y=55/9,
The put the value in any equation then we get x=50m,
Thank you.
Putting the value of x in 2nd so 90y - 81y + 45 = 100,
So after solving, y=55/9,
The put the value in any equation then we get x=50m,
Thank you.
(2)
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