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?
23 m
23$ \dfrac{2}{9} $m
27$ \dfrac{7}{9} $m
29 m
Explanation:
| Relative speed = (40 - 20) km/hr =$ \left(20 \times\dfrac{5}{18} \right) $m/sec =$ \left(\dfrac{50}{9} \right) $m/sec. |
| $\therefore$ Length of faster train =$ \left(\dfrac{50}{9} \times 5\right) $m =$ \dfrac{250}{9} $m = 27$ \dfrac{7}{9} $m. |