Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 4)
4.
Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:
Answer: Option
Explanation:
Let the speeds of the two trains be x m/sec and y m/sec respectively.
Then, length of the first train = 27x metres,
and length of the second train = 17y metres.
 |
27x + 17y | = 23 |
| x+ y |
27x + 17y = 23x + 23y
4x = 6y
| |
x | = | 3 | . |
| y | 2 |
Discussion:
236 comments Page 4 of 24.
K.kiran kumar said:
2 decades ago
I can't get this step
(27x+17y) / (x+y) = 23
Why we have to use this? can any one explain me.
(27x+17y) / (x+y) = 23
Why we have to use this? can any one explain me.
Niveditha said:
2 decades ago
Anyone please help me how this x+y is divided.
Arjun said:
2 decades ago
(27x+17y)/x+y=23 how did used that step?
Janardhan said:
2 decades ago
It's correct method to solve this problem.
Boomathi said:
2 decades ago
very good solution....
Arun said:
2 decades ago
Based on the below formula -- >
If two trains of length a(i.e. 27x) metres and b(i.e. 17y) metres are moving in opposite directions at x m/s and y m/s, then:
The time taken by the trains to cross each other (i.e.23 sec) =
(27x + 17y)
```````` secs
(x + y)
Therefore, the above solution is provided based on this derivation. Its given in the formulas section.
If two trains of length a(i.e. 27x) metres and b(i.e. 17y) metres are moving in opposite directions at x m/s and y m/s, then:
The time taken by the trains to cross each other (i.e.23 sec) =
(27x + 17y)
```````` secs
(x + y)
Therefore, the above solution is provided based on this derivation. Its given in the formulas section.
Mohit sahu said:
2 decades ago
Friends its easy to undrstnd as the qustn says that d trains r moving in oppste drtn that means the total distance travveld by the trains wen they crosses the person will be equal to the total distance travlld by dem in crossng each other.
Mathematly we can also better undrstnd ths by wrtng tht equation as
27x + 17y = 23(x + y).
Mathematly we can also better undrstnd ths by wrtng tht equation as
27x + 17y = 23(x + y).
Vivek said:
2 decades ago
How the (27x+17y)/x+y=23 formula comes?
Sunny(sunil) said:
2 decades ago
http://www.indiabix.com/aptitude/problems-on-trains/formulas
Look at this link then you can understand why we use x+y down there!
Look at this link then you can understand why we use x+y down there!
Sameer said:
2 decades ago
Can anyone explain me how he got this step 4x = 6y ?
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