A 500 m long freight train moving at 60 km/h crosses a river bridge 1 km long. How many seconds does it take?

Explanation

1. 01

   Distance = 500 $m + 1000$ $m = 1500$ m.

2. 02

   60 km/h $= \frac{50}{3}$ m/s.

3. 03

   Time $= 1500 \div \frac{50}{3} = 90$ s.