Question

A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long?

• A. 40 sec
• B. 42 sec
• C. 45 sec
• D. 48 sec

Answer 1

The correct option is A 40 sec

Formula for converting from km/hr to m/s = $Xkm/hr=(X\times \frac{5}{18})m/s$
Therefore,

$Speed=(45\times \frac{5}{18})m/sec=\frac{25}{2}m/sec$

Total distance to be covered $=(360+140)m=500m$.

Formula for finding time $=\left(\frac{Distance}{Speed}\right)$

$\therefore$ Required Time $=\left(\frac{500\times 2}{25}\right)sec=40sec.$