Question

A train of length 150 m takes 10 sec to cross another 100 m long train coming from the opposite direction If the first train is 30 kmph what is the speed of second train?

• A. 72 kmph
• B. 60 kmph
• C. 54 kmph
• D. 48 kmph

Answer 1

The correct option is B 60 kmph

Let the speed of train be x km \hr

Relative speed =$(30+x)\times \frac{5}{15}=\frac{150+5x}{18}kmsec$

$\therefore \frac{150+100}{\frac{150+5x}{18}}=10$

$\Rightarrow 18\times 250=10(150+5x)$

$\Rightarrow 4500=1500+5x$

$\Rightarrow 5x=4500-1500$

$\Rightarrow 5x=3000$

$\Rightarrow x=60km/hr$