Trains Q54

54..	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

Answer: Option D

Explanation:

Let the length of the train be x metres and its speed by y m/sec.

Then,	x	= 8          x = 8y
	y

Now,	x + 264	= y
	20

 8y + 264 = 20y

 y = 22.

Speed = 22 m/sec =		22 x	18		km/hr = 79.2 km/hr.
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