Question

Two friends went rowing on the river. They first traveled with current for 3 hours. The way back took them 4 hours and 48 minutes. Find the speed of the river's current if they can row in still water at a speed of 6.5 mph.

Answer 1

Answer:

The speed of the river current is 1.5 km/h

Step-by-step explanation:

Let the flow of the river be v km/h

Speed of the boat = 6.5 km/h

Speed of the boat when it is being rowed with the current = v + 6.5

Speed of the boat when it is being rowed against the current = 6.5 - v

According to the question

$(v+6.5)\times 3=(6.5-v)\times (4+\frac{48}{60})$

$\implies 3v+19.5=(6.5-v)\times 4.8$

$\implies 3v+19.5=31.2-4.8v$

$\implies 7.8v=11.7$

$\implies v=\frac{11.7}{7.8}$

$\implies v=1.5$ km/h

Therefore, the speed of river current is 1.5 km/h

Hope this helps.