6.

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. None of these
Answer and Explanation
Answer:B
Explanation: Speed = (300 / 18) m/sec = (50 / 3) m/sec. Length of the platform be x metres. Then = x + 300 /39 = 50 / 3 m/sec = 3 (x + 300) =1950 . = 350 m
7.

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.
8.

A train takes 18 seconds to pass completely through a station 162 m long and 15 seconds through another station 120 m long. The length of the train is.
A. 70 m B. 80 m
C. 90 m D. 100 m
Answer and Explanation
Answer:C
Explanation: Let the length of the train be x metres. = x + 162 / 18 = x + 120 / 15 = 15( x+162) = 18(x+120) x= 90.
9.

Two trains of equal lengths take 10 seconds and 15 seconds respectively to cross a telegraph post. If the length of each train be 120 metres, in what time (in seconds) will they cross each other travelling in opposite direction?

A. 10 B. 12
C. 15 D. 20
Answer and Explanation
Answer:B
Explanation: Speed of the first train = ( 120 /10) m/sec = 12 m/sec. Speed of the second train = ( 120 /15) m/sec = 8 m/sec. Relative speed = (12 + 8) = 20 m/sec. Therefore Required time = [ (120 + 120) /20] sec = 12 sec.
10.

How many seconds will a 500 metre long train take to cross a man walking with a speed of 3 krn/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
Answer and Explanation
Answer:B
Explanation: 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.