Two trains 150 meters and 100 meters long are running along parallel tracks in the same direction at speeds of 56 km/h and 46 km/h respectively. In what time will the faster train cross the slower train completely? MCQ with Answer and Explanation
Two trains 150 meters and 100 meters long are running along parallel tracks in the same direction at speeds of 56 km/h and 46 km/h respectively. In what time will the faster train cross the slower train completely?
A. 90 seconds
B. 80 seconds
C. 100 seconds
D. 110 seconds
Answer: Option A
Solution (By JKSSB Mock Tests)
Total distance = 150 + 100 = 250 meters. Relative speed in same direction = 56 - 46 = 10 km/h = 10 * (5/18) = 25/9 m/s. Time required = 250 / (25/9) = 250 * 9 / 25 = 90 seconds.
A sound wave travels at a speed of 330 m/s. If the echo of a sound is heard from a wall after 2 seconds, find the distance of the wall from the source.
Explanation:
Total distance traveled by the sound wave to the wall and back = Speed * Time = 330 * 2 = 660 meters. Distance to the wall = 660 / 2 = 330 meters.
Two cars A and B leave an intersection simultaneously. A travels North at 45 km/h and B travels East at 60 km/h. Find the direct distance between them after 1 hour.
Explanation:
Let each third of the distance be 60 km. Total distance = 180 km. Total time taken = 60/15 + 60/30 + 60/60 = 4 + 2 + 1 = 7 hours. Average speed = 180 / 7 = 25.71 km/h.
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