Time And Distance Problem

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A train M leaves Meerut at 5:00 am and reaches Delhi at 09:00 am. Another train N leaves Delhi at 07:00 am and reaches Meerut at 10:30 am. At what time do the two trains cross one another ?

(a) 8.26 am

(b) 8 am

(c) 7.36 am

(d) 7.56 am

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Hi parthdpatel.patel,

What is the source of this question? And is it a GMAT source or a 'general math' source? I ask because this question is not written in proper GMAT 'style' (it has 4 answers instead of 5 and there are no references to the trains traveling at a constant speed or the same distance). If you're going to be studying for the GMAT, then I highly recommend that you use established GMAT resources.

GMAT assassins aren't born, they're made,
Rich

[talaangoshtari]

The correct answer is D

[theCEO]

A train M leaves Meerut at 5:00 am and reaches Delhi at 09:00 am. Another train N leaves Delhi at 07:00 am and reaches Meerut at 10:30 am. At what time do the two trains cross one another ?

(a) 8.26 am

(b) 8 am

(c) 7.36 am

(d) 7.56 am

Agree with Rich on questioning the source.

Assumption- trains travel at constant speed

First we have to find out where M is when N starts.
If M leaves at 5am and takes 4 hours to reach the end, at 7am M will be at half the distance traveled

Therefore we can rephrase the question to:
M and N leaves at 7am, what time do they meet?

distance = speed x time

distance M travels + distance N travels = total distance*(1/2)
(d/4)*t + (d/3.5)*t = d/2
t(d/4 + d/3.5) = d/2
t = (d/2) / (d/4 + d/3.5) = (d/2) / (2d/8 + 2d/7)
t = (d/2 / (30d/56) = (14/15)hr = 56minutes

Therefore total time = 56minutes + time they both started = 56minutes + 7am = 7.56
ans = d