Question

the speed of a boat in still water is 10km/h.it is rowed upstream for a distance of 45km in 6 hours find the speed of the boat stream​

Answer 1

Question :

The speed of a boat in still water is 10km/h. It is rowed upstream for a distance of 45km in 6 hours. Find the speed of the river stream​.

Answer :

• Speed of river stream = 2.5 km/h

Given :

• Speed of a boat in still water is 10km/h
• It is rowed upstream for a distance of 45km in 6 hours

To find :

• the speed of the river stream​

Solution :

=> Let the speed of the river stream be  $V_w$

=>  Speed of the boat in still water,  $V_b = \text{10 km/h}$

=> it is rowed upstream for a distance of 45km in 6 hours

         Distance covered = 45 km

                 time taken     = 6 hours

=> Upstream speed = speed of boat in still water - speed of the river stream

     Upstream speed = $(10-V_w) \ km/h$

     

We know that,

           speed = distance covered/time taken

By substituting the values,

         

      $10-V_w=\frac{45}{6} \\\\ 6(10-V_w)=45 \\\\ 60-6V_w=45 \\\\ 6V_w=60-45 \\\\ 6V_w=15 \\\\ V_w=\frac{15}{6} \\\\ V_w=\frac{5}{2} \\\\ V_w=2.5 \ km/h$

∴ The speed of the river stream = 2.5 km/h