aptitude

Time and Work

1.A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left is :
A.1/4      

View answer :

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aptitude

1.		A train running at the speed of 60 km/hr crosses a pole in 9 seconds. What is the length of the train?
		A 120 metres B. 180 metres C. 324 metres D. 150 metres Answer & Explanation Answer: Option D Explanation: Speed= 60 x 5 m/sec = 50 m/sec. 18 3 Length of the train = (Speed x Time) = 50 x 9 m = 150 m. 3 View Answer Workspace Report Discuss in Forum

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2.	A train 125 m long passes a man, running at 5 km/hr in the same direction in which the train is going, in 10 seconds. The speed of the train is:
	45 km/hr B. 50 km/hr C. 54 km/hr D. 55 km/hr Answer & Explanation Answer: Option B Explanation: Speed of the train relative to man = 125 m/sec 10    = 25 m/sec. 2    = 25 x 18 km/hr 2 5    = 45 km/hr. Let the speed of the train be x km/hr. Then, relative speed = (x - 5) km/hr.  x - 5 = 45          x = 50 km/hr. View Answer Workspace Report Discuss in Forum

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3.	The length of the bridge, which a train 130 metres long and travelling at 45 km/hr can cross in 30 seconds, is:
	A. 200 m B. 225 m C. 245 m D. 250 m Answer & Explanation Answer: Option C Explanation: Speed = 45 x 5 m/sec = 25 m/sec. 18 2 Time = 30 sec. Let the length of bridge be x metres. Then, 130 + x = 25 30 2  2(130 + x) = 750  x = 245 m. View Answer Workspace Report Discuss in Forum

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4.	Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:
	A. 1 : 3 B. 3 : 2 C. 3 : 4 D. None of these Answer & Explanation Answer: Option B Explanation: Let the speeds of the two trains be x m/sec and y m/sec respectively. Then, length of the first train = 27x metres, and length of the second train = 17y metres. 27x + 17y = 23 x+ y  27x + 17y = 23x + 23y  4x = 6y x = 3 . y 2 View Answer Workspace Report Discuss in Forum

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5.	A train passes a station platform in 36 seconds and a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, what is the length of the platform?
	A. 120 m B. 240 m C. 300 m D. None of these Answer & Explanation Answer: Option B Explanation: Speed = 54 x 5 m/sec = 15 m/sec. 18 Length of the train = (15 x 20)m = 300 m. Let the length of the platform be x metres. Then, x + 300 = 15 36  x + 300 = 540  x = 240 m. View Answer Workspace Report Discuss in Forum 6.  A train 240 m long passes a pole in 24 seconds. How long will it take to pass a platform 650 m long? A. 65 sec B. 89 sec C. 100 sec D. 150 sec Answer & Explanation Answer: Option B Explanation: Speed = 240 m/sec = 10 m/sec. 24  Required time = 240 + 650 sec = 89 sec. 10 View Answer Workspace Report Discuss in Forum 7.  Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is: A. 50 m B. 72 m C. 80 m D. 82 m Answer & Explanation Answer: Option A Explanation: Let the length of each train be x metres. Then, distance covered = 2x metres. Relative speed = (46 - 36) km/hr    = 10 x 5 m/sec 18    = 25 m/sec 9 2x = 25 36 9  2x = 100  x = 50. View Answer Workspace Report Discuss in Forum 8.  A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long? A. 40 sec B. 42 sec C. 45 sec D. 48 sec Answer & Explanation Answer: Option A Explanation: Formula for converting from km/hr to m/s:   X km/hr = X x 5 m/s. 18 Therefore, Speed = 45 x 5 m/sec = 25 m/sec. 18 2 Total distance to be covered = (360 + 140) m = 500 m. Formula for finding Time = Distance Speed  Required time = 500 x 2 sec = 40 sec. 25 View Answer Workspace Report Discuss in Forum 9.  Two trains are moving in opposite directions @ 60 km/hr and 90 km/hr. Their lengths are 1.10 km and 0.9 km respectively. The time taken by the slower train to cross the faster train in seconds is: A. 36 B. 45 C. 48 D. 49 Answer & Explanation Answer: Option C Explanation: Relative speed = (60+ 90) km/hr    = 150 x 5 m/sec 18    = 125 m/sec. 3 Distance covered = (1.10 + 0.9) km = 2 km = 2000 m. Required time = 2000 x 3 sec = 48 sec. 125 View Answer Workspace Report Discuss in Forum 10.  A jogger running at 9 kmph alongside a railway track in 240 metres ahead of the engine of a 120 metres long train running at 45 kmph in the same direction. In how much time will the train pass the jogger? A. 3.6 sec B. 18 sec C. 36 sec D. 72 sec Answer & Explanation Answer: Option C Explanation: Speed of train relative to jogger = (45 - 9) km/hr = 36 km/hr.    = 36 x 5 m/sec 18    = 10 m/sec. Distance to be covered = (240 + 120) m = 360 m.  Time taken = 360 sec = 36 sec. 10 11.  A 270 metres long train running at the speed of 120 kmph crosses another train running in opposite direction at the speed of 80 kmph in 9 seconds. What is the length of the other train? A. 230 m B. 240 m C. 260 m D. 320 m E. None of these Answer & Explanation Answer: Option A Explanation: Relative speed = (120 + 80) km/hr    = 200 x 5 m/sec 18    = 500 m/sec. 9 Let the length of the other train be x metres. Then, x + 270 = 500 9 9  x + 270 = 500  x = 230. View Answer Workspace Report Discuss in Forum 12.  A goods train runs at the speed of 72 kmph and crosses a 250 m long platform in 26 seconds. What is the length of the goods train? A. 230 m B. 240 m C. 260 m D. 270 m Answer & Explanation Answer: Option D Explanation: Speed = 72 x 5 m/sec = 20 m/sec. 18 Time = 26 sec. Let the length of the train be x metres. Then, x + 250 = 20 26  x + 250 = 520  x = 270. View Answer Workspace Report Discuss in Forum 13.  Two trains, each 100 m long, moving in opposite directions, cross each other in 8 seconds. If one is moving twice as fast the other, then the speed of the faster train is: A. 30 km/hr B. 45 km/hr C. 60 km/hr D. 75 km/hr Answer & Explanation Answer: Option C Explanation: Let the speed of the slower train be x m/sec. Then, speed of the faster train = 2x m/sec. Relative speed = (x + 2x) m/sec = 3x m/sec. (100 + 100) = 3x 8  24x = 200  x = 25 . 3 So, speed of the faster train = 50 m/sec 3    = 50 x 18 km/hr 3 5    = 60 km/hr. View Answer Workspace Report Discuss in Forum 14.  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 & Explanation Answer: Option D Explanation: Relative speed = (60 + 40) km/hr = 100 x 5 m/sec = 250 m/sec. 18 9 Distance covered in crossing each other = (140 + 160) m = 300 m. Required time = 300 x 9 sec = 54 sec = 10.8 sec. 250 5 View Answer Workspace Report Discuss in Forum 15.  A train 110 metres long is running with a speed of 60 kmph. In what time will it pass a man who is running at 6 kmph in the direction opposite to that in which the train is going? A. 5 sec B. 6 sec C. 7 sec D. 10 sec Answer & Explanation Answer: Option B Explanation: Speed of train relative to man = (60 + 6) km/hr = 66 km/hr.    = 66 x 5 m/sec 18    = 55 m/sec. 3  Time taken to pass the man = 110 x 3 sec = 6 sec.
16.	A train travelling at a speed of 75 mph enters a tunnel 3 miles long. The train is mile long. How long does it take for the train to pass through the tunnel from the moment the front enters to the moment the rear emerges?
	A. 2.5 min B. 3 min C. 3.2 min D. 3.5 min Answer & Explanation Answer: Option B Explanation: Total distance covered = 7 + 1 miles 2 4 = 15 miles. 4  Time taken = 15 hrs 4 x 75 = 1 hrs 20 = 1 x 60 min. 20 = 3 min. View Answer Workspace Report Discuss in Forum

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17.	A train 800 metres long is running at a speed of 78 km/hr. If it crosses a tunnel in 1 minute, then the length of the tunnel (in meters) is:
	A. 130 B. 360 C. 500 D. 540 Answer & Explanation Answer: Option C Explanation: Speed = 78 x 5 m/sec = 65 m/sec. 18 3 Time = 1 minute = 60 seconds. Let the length of the tunnel be x metres. Then, 800 + x = 65 60 3  3(800 + x) = 3900  x = 500. View Answer Workspace Report Discuss in Forum

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18.	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 & Explanation Answer: Option B Explanation: Speed = 300 m/sec = 50 m/sec. 18 3 Let the length of the platform be x metres. Then, x + 300 = 50 39 3  3(x + 300) = 1950  x = 350 m. View Answer Workspace Report Discuss in Forum

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19.	A train speeds past a pole in 15 seconds and a platform 100 m long in 25 seconds. Its length is:
	A. 50 m B. 150 m C. 200 m D. Data inadequate Answer & Explanation Answer: Option B Explanation: Let the length of the train be x metres and its speed by y m/sec. Then, x = 15          y = x . y 15 x + 100 = x 25 15  15(x + 100) = 25x  15x + 1500 = 25x  1500 = 10x  x = 150 m. View Answer Workspace Report Discuss in Forum

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20.	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 & Explanation 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. 5 View Answer Workspace Report Discuss in Forum

aptitude

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