Question

The speed of current is 5 km/h. What will be the respective downstream speed and upstream speed of a boy rowing a boat, if one third of the distance covered going downstream in a certain time is equal to the distance covered going upstream in the same time.

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Answer 1

Answer:

$\rightarrow \small \bf Downstream\:Speed =15km/h.$

$\rightarrow \small \bf Upstream\: Speed=5km/h.$

Step-by-step explanation:

Your Question:

The speed of current is 5 km/h. What will be the respective downstream speed and upstream speed of a boy rowing a boat, if one third of the distance covered going downstream in a certain time is equal to the distance covered going upstream in the same time.

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Given:

• The speed of current is 5 km/h.

• If one third of the distance covered going downstream in a certain time is equal to the distance covered going upstream in the same time.

To find out:

The respective downstream speed and upstream speed of a boy rowing a boat.

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Explanation:

Let the speed of boy is still water be X km/h.

And the speed of current is given = 5km/h.

Then,

Downstream speed = (x + 5)km/h.

Upstream speed = (x - 5)km/h.

Let time be 't' hours.

Then equation is:-

$\implies \dfrac{(x + 5)t}{3} = (x - 5)t \\ \\ \implies\dfrac{(x + 5) \cancel{t}}{3} = (x - 5) \cancel{t} \\ \\ \implies x + 5 = (x - 5)3 \: \: \: \: \: \: \\ \\ \implies x + 5 =3x - 15 \: \: \: \: \: \: \: \\ \\ \implies x - 3x = - 15 - 5 \: \: \: \\ \\ \implies \cancel{-} 2x = \cancel{-}20 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \implies 2x = 20 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \implies x = \bf 10 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \:$

Hence,

X is equal to 10 then,

Downstream Speed = (x + 5) = 15km/h.

Upstream Speed = (x -5) = 5km/h.

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Answer:

→ Downstream Speed = 15km/h.

→ Upstream Speed = 5km/h.

Answer 2

Answer:

Downstream = 15 km/h

Upperstream = 5 km/h