Aptitude - Problems on Trains - Discussion

First take 220/6=36.66 m/s.

Now convert into km/h so 132km/h.
and minus 50km/h from 132 - 50 = 82km/h.
Thanks.

We have got v (kmph) if it had been v * 5/18 then we would have gotten speed in m/s.

@Ashok.

How you get 220/250 + 5x/18?

Sorry I make a mistake in my last comment.

D = 108 + 112 = 120.
Converting the speed of 1st Train = 50x 5/18 m/s.
Let the speed of 2nd Train= V m/s.

We get,

220/ (50x 5/18) + V = 6 sec.

=> 220= 6x(250+18V)/18,
=> 220=(250+18V)/3,
=>660= 250+18V,
=>18V=410,
=> V= 410/18 m/s.

Converting the speed of the second Train we Get,
=> (410/18) x (18/5).
=> 82 Kmph.

This is the right answer

D = 108 + 112 = 120
Converting the speed of 1st Train = 50x 5/18 m/s
Let the speed of 2nd Train= V m/s

We get,

220/ (50x 5/18) + V = 6 sec

=> 220= 6x(250+18V)/18,
=> 220=(250+18V)/3,
=>660= 250+18V,
=>18V=390,
=> V= 390/18 m/s.

Converting the speed of the second Train we Get
=> (390/18) x (18/5)
=> 78 Kmph.

This is the right answer

The solution is not clear for it. Can anybody solve it easily?

220/6 = 250 + 5x/18,
By solving it we get,
3960 = 1500 + 30x,
2460 = 3x,
So, x = 82.

Sir, if the train is moving in an opposite direction the total distance one has to cover is the larger length. So why have we added the two?

How Comes 5 in answer? I can't Understand please explain this.

Hey @Prity and @Prem
See
(1) S km/hr = S.5/18 m/sec
(2) S m/sec = S.18/5 km/hr

That's why
50.5/18 -X.5/18 = 220/6 m/sec
250/18 -X.5/18 = 220/6 m/sec
- X.5/18 = 220/6 . 18 /250 m/sec

Now all are in m/ sec but now the game will be changed
Suppose if I move 5/18 from left side to right side so according to second rule m/sec. 18/5 =km/hr

-X = 220/6. 18 /250. (5/18) the value will be in km/hr
After all the calculation you will get the same answer in km/hr.

I hope you got the logic behind it.