Question

A train $300$ m long crossed a platform $900$ m long in $1$ min $12$ s. The speed of the train is :

• A. $45$ km/hr
• B. $50$ km/hr
• C. $60$ km/hr
• D. $55$ km/hr

Answer 1

The correct option is C $60$ km/hr

Time =1 min 12 s=72 s

Distance covered in 72 second =300+900=1200 m

$Speed=\frac{distance}{time}$

$Speed=\left(\frac{1200}{72}\right)m/sec=\left(\frac{50}{3}\right)m/sec=(\frac{50}{3}\times \frac{18}{5})=60km/hr$