36.

Two stations P and Q are 110 km apart on a straight track. One train starts from P at 7 a.m. and travels towards Q at 20 kmph. Another train starts from Q at 8 a.m. and travels towards P at a speed of 25 kmph. At what time will they meet?

A. 10.30 B. 10
C. 8.45 D. 9.30
Answer and Explanation
Answer:B
Explanation: Assume both trains meet after x hours after 7 am Distance covered by train starting from P in x hours = 20x km Distance covered by train starting from Q in (x-1) hours = 25(x-1) Total distance = 110 => 20x + 25(x-1) = 110 => 45x = 135 => x= 3 Means, they meet after 3 hours after 7 am, ie, they meet at 10 am
37.

Two trains having equal lengths, take 10 seconds and 15 seconds respectively to cross a post. If the length of each train is 120 meters, in what time (in seconds) will they cross each other when traveling in opposite direction?

A. 10 B. 25
C. 12 D. 20
Answer and Explanation
Answer:C
Explanation: speed of train 1 = 120/10 = 12 m/s speed of train 2 = 120/15 = 8 m/s if they travel in opposite direction, relative speed = 12 + 8 = 20 m/s distance covered = 120 + 120 = 240 m time = distance/speed = 240/20 = 12 s
38.

A 300 metre long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform ?

A. 320 m B. 350 m
C. 650 m D. data inadequate
Answer and Explanation
Answer:B
Explanation: Speed = m/sec = m/sec. Let the length of the platform be x metres. Then, = 3(x+300) = 1950 x = 350m
39.

A train moves with a speed of 108 kmph. Its speed in metres per second is :

A. 10.8 B. 18
C. 30 D. 38.8
Answer and Explanation
Answer:C
Explanation: 108 kmph =(108*5/18) = 30 m / s.
40.

Two trains 140 m and 160 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other, is:

A. 9 B. 9.6
C. 10 D. 10.8
Answer and Explanation
Answer:D
Explanation: Relative speed = (60 + 40) km/hr =[ 100 x ( 5 / 18 ) ]m/sec = ( 250 /9 ) m/sec. Distance covered in crossing each other = (140 + 160) m = 300 m. Required time = [ 300 x ( 9/250 ) ] sec = ( 54/ 5 )sec = 10.8 sec.