A train running at $40 \frac{1}{2}$ km/h takes 24 seconds to cross a pole. How much time (in seconds) will it take to pass a 450 m long bridge ?
Answer & explanation
Correct answer: option 4
Distance = Speed × Time
Speed = \(\frac{81}{2}\) km/h = \(\frac{81}{2}\) × \(\frac{5}{18}\) = 11.25 m/sec
Length of train = 11.25 × 24 = 270 m
Now ,
Total distance = Length of train + length of bridge
= 270 + 450 = 720 m
Time taken = \(\frac{720}{11.25}\) = 64 sec