41. A man sitting in a train which is traveling at 50 km/hr observes that a good train traveling in opposite direction takes 9 seconds to pass him. If the goods train is 280 m long find its speed?

A. 65 km/hr B. 60 km/hr C. 64 km/hr D. 62 km/hr

Answer Answer: Option D Explanation: Relative speed =(280/9) m/sec = (280/9*18/5) km/hr = 112 km/hr
Hence speed of the goods train =(112 - 50) = 62km/hr

42. A train running at 54 km/ph takes 20 seconds to pass a platform.Next it takes 12 seconds to pass a man walking at 6km/ph in the same direction in which the train is going.Find the length of the train and the length of the platform?

A. 135 m B. 142 m C. 140 m D. 138 m

Answer Answer: Option C Explanation: Let the length of the train be X meters and length of platform be Y meters.
Speed of the train relative to man = (54-6) km/ph =48 km/ph = (48*5/18)m/sec = 40/3 m/sec
In passing a man the train covers its own length with relative speed.
Length of train =(relative speed * time) = (40/3*12)m =160m
Also speed of the train =(54*5/18)m/sec = 15 m/sec
Hence x+y/15 =20
x+y = 300
y= (300 -160) m = 140 m

43. A train 100 meters long take as 6 seconds to cross a man walking at 5 km/hr.In a direction opposite to that of the train.Find the speed of the train?

A. 57 km/hr B. 55 km/hr C. 48 km/hr D. 50 km/hr

Answer Answer: Option B Explanation: Let the speed of the train be X km/hr
Speed of the train relative to man = (X+5) km/hr = (X+5) * 5/18 m/sec
100/(X+5)*5/18 = 6
30(X+5) = 1800 = X=55
Speed of the train is 55 Km/ph

44. Two trains 100 meters and 120 meters long are running in the same direction with speed of 72 km/hr and 54 km/hr in how much time will the first train cross the second?

A. 44 sec B. 46 sec C. 42 sec D. 48 sec

Answer Answer: Option A Explanation: Relative speed of the trains = (72-54 = 18 km/hr)
= (18*5/18) m/sec = 5m /sec
Time taken by the trains to cross each other
= Time taken to cover (100+120)m at 5 m/sec = (220/5)sec = 44 sec

45. Two trains 137 meters and 163 meters in length are running towards each other on parallel lines, one at the rate of 42 km/hr and another at 48 km/hr. In what time will they be clear of each other from the moment they meet?

A. 10 seconds B. 12 seconds C. 15 seconds D. 20 seconds

Answer Answer: Option B Explanation: Relative speed of the trains = (42+48) km/hr = 90km/hr
= (90*5/18) m/sec = 25 m/sec
time taken by the trains to pass each other
= Time taken to cover (137+163)m at 25 m/sec = (300/25) sec = 12 seconds.