41.A train moves past a telegraph post and a bridge 264 m long in 8 seconds and 20 seconds respectively. What is the speed of the train?
A. 69.5 km/hr
B. 70 km/hr
C. 79 km/hr
D. 79.2 km/hr
Option:D
Let the length of the train be x metres and its speed by y m/sec.
⇒ 8y + 264 = 20y⇒ y = 22.
∴ Speed = 22 m/sec =
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22 x
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18
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km/hr = 79.2 km/hr.
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5
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