Question

The respective ratio of the speed of a boat upstream and its speed downstream is 2 : 3. the speed of the boat in still water is 14 kmph, how much distance the boat can travel upstream in 24 minutes ? (in km)

Answer 1

Given:

The respective ratio of the speed of a boat upstream and its speed downstream is 2 : 3. the speed of the boat in still water is 14 kmph.

To find:

Distance the boat can travel upstream in 24 minutes ?

Calculation:

Let velocity of boat in still water be u , velocity of stream be v :

As per question , u = 14 km/hr.

$\therefore \: \dfrac{upstream \: speed}{downstream \: speed} = \dfrac{2}{3}$

$\implies \: \dfrac{u - v}{u + v} = \dfrac{2}{3}$

$\implies \: 3u - 3v = 2u + 2v$

$\implies \: u = 5v$

$\implies \: v = \dfrac{u}{5}$

$\implies \: v = \dfrac{14}{5}$

$\implies \: v = 2.8 \: km/hr$

So, upstream speed = 14 - 2.8 = 11.2 km/hr.

$\therefore \: d = speed \times time$

$\implies \: d = 11.2 \times \dfrac{24}{60}$

$\implies \: d = 11.2 \times \dfrac{2}{5}$

$\implies \: d = 4.48 \: km$

So, distance travelled upstream is 4.48 km.