Question

A train, $600$ metres long is running at $80$ km/hr. How much time will the train take to cross the driver sitting in another train that is $400$ metres long, running at $64$ km/hr in the opposite direction?

• A. $10$ seconds
• B. $5$ seconds
• C. $15$ seconds
• D. $20$ seconds

Answer 1

The correct option is C $15$ seconds

As the trains are running in opposite direction,
relative speed $=80+64=144$ km/hr $=144\times \frac{5}{18}=40$ m/s
Now, speed $=\frac{\text{Distance}}{\text{Time}}$
$\Rightarrow \text{Time}=\frac{600}{40}=15$ seconds