Aptitude - Problems on Trains - Discussion

What to do if asked length of a slower train? Anyone, please explain to me.

Can someone explain why we take 5/18 in the km/hr? I am not getting it.

@Siddarth.

You don't need to divide 250/9 completely because we don't need the answer in decimals according to the options.

You should divide 250 by 9 until you cannot divide it further without the need of a decimal i.e. when the quotient is 27 and the remainder is 7.

And then you can write it in the form of a mixed fraction i.e. quotient remainder/divisor or 27 7/9 as given in option C.

250 /9 = 27.777777778 means then how to convert it into 27*7/9?

Please explain in detail.

Why we don't count two train lengths? Anyone explain me.

@Dwivedi.

Here what they asked is, the length of the faster train.

If you want the length generally we multiply speed and time.

In this question, you think that you are in a slower train it's speed is 20kmph in which ever the place either in front middle or in last your speed is 20kmph. The faster train has to cross you so the speed of train relative to you is 20kmph or 50/9mps.

Length of the faster train = relative speed in mps*time in sec = 50/9 * 5 = 250/9 = 27 * 7/9.
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This question definitely depends upon where the person is sitting in the second train - middle, end or int engine of the train depending on which the total time taken by the fast train to pass him completely will change. And the solution given is correct only if the person is sitting at the end of the slower train. Can someone explain this, please?

I think if they asked to find the length of the smaller train we have to use same formula as explained above in explaination box. We can assume that length of two trains are same.

Divide 250 by 9. The Remainder * Quotient/Divisor rule then follows.

@Shital.

It is a mixed fraction method, 27 * 9 = 243.
243 + 7 = 250.