Problems on Trains - Arithmetic Aptitude Questions and Answers

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What is the speed of the train whose length is 210 metres?

I. The train crosses another train (Howrah Express/12869) of 300 metres length running in opposite direction in 10 seconds.

II. The train crosses another train (Howrah Express/12869) running in the same direction at the speed of 60 km/hr in 30 seconds.

I alone sufficient while II alone not sufficient to answer

II alone sufficient while I alone not sufficient to answer

Either I or II alone sufficient to answer

Both I and II are not sufficient to answer

Both I and II are necessary to answer

Answer : Option E

Explanation :

Time taken to cross the train, running in opposite directions	=		\(\frac { (l1+l2) } { (u+v) } sec\)

10 = \(\frac { (210+300) } { (u+v) } \)

u + v = 51.

Time taken to cross the train, running in same direction =		\( \frac { (l1+l2) } { (u-v) } sec\)sec.

30 = \(\frac { (210+300) } { ((u-60) \times(5/8))} sec\)