Question

Two trains are running at 40 km/hr and 20 km/hr respectively in the same direction. Fast train completely passes a man sitting in the slower train in 5 seconds. What is the length of the fast train? 

(a) 23 m 

(b) \(23\frac29\) m 

(c) 27 m 

(d) \(27\frac79\) m

Answer 1

(d)   \(27\frac79\) m

Relative speed = (40 – 20) km/hr

= \(\bigg(20\times\frac{5}{18}\bigg)\) m/x = \(\frac{50}{9}\) m/s.

∴ Length of the faster train = \(\bigg(\frac{50}{9}\times5\bigg)\) m

= \(\frac{250}{9}\) m =  \(27\frac79\) m