Subject
Quantitative Aptitude
Topic
Speed & Distance
A steamer goes downstream from one port to another in 2 hours. It covers the same distance upstream in 3 hours. If the speed of stream is 4 km/h, the distance between the two ports is
A steamer goes downstream from one port to another in 2 hours. It covers the same distance upstream in 3 hours. If the speed of stream is 4 km/h, the distance between the two ports is
ক)
16 kmখ)
24 kmগ)
20 kmঘ)
48 kmঙ)
40 kmExplanation
Let the distance from one port to another is = d Let speed of boat is = x Given, time in downstream = 2 hr ∵ Time = distance/(Speed in downstream) Speed of motorboat in downstream = speed of boat + speed of stream ∴ speed of motorboat in downstream = x + 4 ∴ 2 = d/(x + 4) ⇒ d = 2x + 8 Given, time in upstream = 3 hr ∵ Time = distance/(speed in upstream) Speed of motorboat in upstream = speed of boat – speed of stream ∴ speed of motorboat in upstream = x – 4 ∴3 = d/(x - 4) ⇒ d = 3x – 12 Distance will be equal so ⇒ 2x + 8 = 3x – 12 ⇒ x = 20 ∵ Distance = speed × time ⇒ d = (20 – 4) × 3 ⇒ d = 48 kmRelated questions
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