Men are running along a road at 15 km/h behind one another at equal intervals of 20m.Cyclists
riding in the same direction at 25 km/h at equal intervals of 30 m. At what speed in km/hr an observer
travel along the road in opposite direction so that whenever he meets a runner he also meets a cyclist
Answers
Answer:
5 km/Hr
Explanation:
Men are running along a road at 15 km/h behind one another at equal intervals of 20m.Cyclists riding in the same direction at 25 km/h at equal intervals of 30 m. At what speed in km/hr an observer travel along the road in opposite direction so that whenever he meets a runner he also meets a cyclist
Speed of Runner = 15 km/hr = 15 * 1000/3600 = 25/6 m/s
Speed of cyclist = 25 km/hr = 25 * 1000/3600 = 125/18 m/s
Distance Covered by Observer = x m
Then Distance Covered by Runner & Cyclist = 20 -x & 30 - x
Time taken by cyclist & Runner is same
( 20 -x)/(25/6) = ( 30 -x)/(125/18)
=> 5 (20-x) = 3 (30 -x)
=> 100 - 5x = 90 - 3x
=> 2x = 10
=> x = 5
Time taken by runner = (20 - 5)/(25/6) = 90/25 = 18/5 = 3.6 sec
Speed of Observer = 5 / (18/5) = 25/18 m/s
= (25/18) * 3600/1000 km/hr
= 5 km/Hr
Answer:
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