A man can row a distance of 8 km downstream in a certain time and can row 6 km upstream in the same time. If he rows 24 km upstream and the same distance downstream in \(1\frac{3}{4}\) hours, then the speed (in km/h) of the current is:

Question

Question

This question was previously asked in

SSC CGL 2020 Tier-I Official Paper 9 (Held On : 17 Aug 2021 Shift 3)

Answer 1

Given:

Total distance = 24km

Time taken = 7/4 hours

Concept used:

Speed = D/t

D= Distance

t = time

Calculation:

Let the speed of man and current be v and s respectively.

According to the question,

\({8\over v \;+\;s} = {6\over v \;-\;s}\)

⇒ 8v - 8s = 6v + 6s

⇒ 2v = 14s

⇒ v : s = 7 : 1

Let speed of man = 7x

Speed of current = x

So,

24/8x + 24/6x = 7/4

⇒ 3/x + 4/x = 7/4

⇒ 7/x = 7/4

⇒ x = 4

⇒ speed of the current = 4 km/h

∴ The speed of the current is 4 km/h

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