Math, asked by kirthi1, 1 year ago

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


karneet: the ratio of the speed is? we need to find that out?
Anupkashyap: can you please make the question more clear...

Answers

Answered by Anonymous
2
Let the lengths of the trains be x, y. Then the velocities of the trains are x/27, y/17. When they cross each other each one has to cover the other train's length and its own length hence the relative velocity is (x+y)/23=x/27+y/17. Solving this you get x/y=81/34

Anupkashyap: can you please explain how you could relate the relative velocity to the sum of individual velocities
Anonymous: Relative velocity is the sum of individual velocities when the objects move in opposite directions
Anonymous: In this case since any one of the trains has to travel a total distance of x+y in 23 seconds it's (x+y)/23
karneet: woah. ur absolutely rite :O
Anupkashyap: Yup got it.. thanx..
kirthi1: no this is not the correct answer
kirthi1: 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/ x+ y = 23

27x + 17y = 23x + 23y

4x = 6y

x = 3 .
y = 2
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