A train with 72 km/h speed crosses a stationary pole in 35 seconds. How much time (in minutes) does it take to cross a 1.1 km long bridge?
Answer & explanation
Correct answer: option 4
Speed of train = 72 km/h
72 km/h = 72 × \(\frac{5}{18}\) m/sec = 20 m/sec
Distance = Speed × Time
= 20 × 35 = 700 m
Now ,
Time taken by train to cross 1.1 km long bridge = 1100 + 700 = 1800 m
Time = \(\frac{Distance}{Speed}\)
= \(\frac{1800}{20 }\)
= 90 seconds
= 1.5 minutes