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A steamer goes downstream from one part to another in 4 hours. It covers the same distance upstream in 5 hours. If the speed of stream is 2 km/hr, the distance between the two ports is:
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Question: A steamer goes downstream from one part to another in 4 hours. It covers the same distance upstream in 5 hours. If the speed of stream is 2 km/hr, the distance between the two ports is:
Solution:
Let, the distance between the two parts = 'x' km
and the speed of steamer in still water = 'y' km/hr
ATQ,
x/(y + 2) = 4
⇒ x = 4y + 8 …. (1)
And, x/(y - 2) = 5
⇒ x = 5y - 10 ….. (2)
From (1) and (2)⇒
4y + 8 = 5y - 10
⇒ y = 18
∴ From (1)
x = 4 × 18 + 8
⇒ x = 80 km.
Solution:
Let, the distance between the two parts = 'x' km
and the speed of steamer in still water = 'y' km/hr
ATQ,
x/(y + 2) = 4
⇒ x = 4y + 8 …. (1)
And, x/(y - 2) = 5
⇒ x = 5y - 10 ….. (2)
From (1) and (2)⇒
4y + 8 = 5y - 10
⇒ y = 18
∴ From (1)
x = 4 × 18 + 8
⇒ x = 80 km.