a2zinterviews

30.	How many seconds will a 500 metre long train take to cross a man walking with a speed of 3 km/hr in the direction of the moving train if the speed of the train is 63 km/hr?
	A.  25
	B.  30
	C.  40
	D.  45

Solution

Speed of train relatively to man = ( 63 - 3)km/hr = 60 km /hr = (60 x 5 / 18)m/sec = (50 /3) m/sec Time taken to pass the man = (500 x 3 / 50)sec = 30 sec.

31.	Two trains 200 m and 150 m long are running on parallel rails at the rate of 40 kmph and 45 kmph respectively. In how much time will they cross each other, if they are running in the same direction?
	A.  72 sec
	B.  132 sec
	C.  192 sec
	D.  252 sec

Solution

Relative Speed = (45 - 40 ) Kmph = 5 kmph =(5 x 5 / 18)m/sec = (25 / 18 ) m/sec Time taken = (350 x 18 / 25) sec = 252 sec.

32.	A train 110 m long passes a man, running at 6 kmph in the direction opposite to that of the train, in 6 seconds The speed of the train is
	A.  54 km/hr
	B.  60 km/hr
	C.  66 km/hr
	D.  72 km/hr

Solution

Speed of the train relative to man = (110 / 6 ) m/sec = (110 / 6 x 18 /5) km/hr = 66 km/hr speed of the train be x kmph. Relative Speed =(x + 6 ) kmph. = x + 6 = 66 x = 60.