Question

two trains of same length but with different speed pass a static pole in 5 second hand 6 seconds respectively in what time will they cross Each Other when they are moving in the same direction

Answer 1

Length of the train = l meter.

Speed of the two trains are l/5 and l/6.

Total distance = 2l.

In same direction Relative speed is (l/5 - l/6).

= l/5 - l/6 = l/30.

Required Time = Distance/Speed.

= 2l/(l/30) = 60 seconds.

Shortcut method:

Formula = 2(Product of time taken)/Difference of time taken.

= 2(6 * 5)/(6 - 5) = 2 * 30 = 60 seconds.

Answer 2

The answer is 60 seconds.

GIVEN

Two trains of same length but with different speed pass a static pole in 5 second hand 6 seconds respectively.

TO FIND

Time they will cross each other.

SOLUTION

We can simply solve the above problem as follows;

Let the length of the trains be L meters

Speed of First train = (L/5) m/s

Speed of the second train = (L/6)m)/s

Since both trains are running in same direction,

Relative speed =

$\frac{L}{5} - \frac{L}{6} = \frac{6L - 5L}{30} = \frac{L}{30}ms^{ - 1}$

Time taken to cross each other;

Time = distance/speed

$t = \frac{2l}{ \frac{l}{30} }$

t = 2 × 30 = 60 seconds.

Hence, The answer is 60 seconds.

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