Question
Download Solution PDFA man rows upstream 15 km and downstream 18 km, he takes 3 hours each time. The speed of the current is:
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFGiven data:
Distance travelled upstream = 15 km
Distance travelled downstream = 18 km
Time taken to travel upstream = Time taken to travel downstream = 3 hours
Formula Used:
Speed of the current = (Downstream speed - Upstream speed) ÷ 2
Calculation:
Calculate the speeds of man (m) and current (c)
⇒ Upstream speed = distance ÷ time = 15 km ÷ 3 h = 5 km/h (m - c = 5 km/h)
⇒ Downstream speed = distance ÷ time = 18 km ÷ 3 h = 6 km/h (m + c = 6 km/h)
Solving these equations for c:
⇒ c = (m + c - m + c) ÷ 2 = (6 km/h - 5 km/h) ÷ 2 =
Therefore, the speed of the current is
Alternate Method Let, the speed of the boat = x
Speed of Stream = y
⇒ x + y = 6 km\hr
⇒ x - y = 5 km/hr
⇒ x = 11/2 km/hr and y = 1/2 km/hr.
∴ The speed of Current is 1/2 km/hr.
Last updated on Jul 8, 2025
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