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A person, rowing at the rate of 5 km/h in still water, takes thrice as much time in going 40 km upstream as in going 40 km downstream. Find the speed of the stream.

Solution:

Consider v km/h as the speed of the stream.

Given,

Speed of a person rowing in still water = 5 km/h.

Speed of a person rowing in downstream = (5 + ν ) km/h.

Speed of a person has rowing upstream = (5 - ν ) km/h.

Time taken by the person to cover 40 km downstream,

t₁ = 40/5+v hours.

Time taken by the person to cover 40km upstream,

t₂ = 40/5-v hours.

According to the given condition,

t₂ = t₁ x 3.

40/5-v = 40/5+v x 3.

1/5-v = 3/5+v

Let us solve this linear equation.

5+ v = 15 - 3v = 4v = 10

v = 10/4

v = 2.5km/h.

Therefore, the speed of the stream is 2.5 km/h.

✦ Try This: A person, rowing at the rate of 6 km/h in still water, takes thrice as much time in going 60 km upstream as in going 20 km downstream. Find the speed of the stream

☛ Also Check: NCERT Solutions for Class 10 Maths Chapter 3

NCERT Exemplar Class 10 Maths Exercise 3.4 Problem 7

A person, rowing at the rate of 5 km/h in still water, takes thrice as much time in going 40 km upstream as in going 40 km downstream. Find the speed of the stream

Summary:

A person, rowing at the rate of 5 km/h in still water, takes thrice as much time in going 40 km upstream as in going 40 km downstream. The speed of the stream is 2.5 km/h.

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