Discussion Forum

What is the length of a running train $A$ crossing another running train $B$ ?

I. These two trains take $18$ seconds to cross to each other.

II. These trains are running in opposite directions.

III. The length of the train $B$ is $180$ metres.

Answer:

Explanation:

Let the length of the train $A$ be $x$ metres.

II. These trains are running in opposite directions.

III. Length of the train $B$ is $180$ m.

I. Time taken by $A$ to cross $B$ $=\frac{(180+x)}{Relative\quad speed}$ $\Rightarrow 18$ $=\frac{(180+x)}{Relative\quad speed}$

Thus, even with I, II and III, the answer cannot be obtained.

$\therefore$ Correct answer is (E).