Question

a boat travels a distance of 80km in 4 hours upstream and same distance down stream in 2hours in a river then the velocities of boat and stream are (in kmph)

Answer 1

Given :

The distance travelled by the boat = 80 km

Time taken by the boat to travel upstream = 4 hours

Time taken by the boat to travel down stream = 2 hours

To Find :

The velocities of boat and the river

Solution :

• Let us assume the velocities of boat and the river be v₁ and v₂

• We know thw relation

               $Velocity=\frac{Distance}{Time}$

               $v_{1} +v_{2}=\frac{80}{4} =20\rightarrow Equation(1)$

               $v_{1} -v_{2}=\frac{80}{2} =40\rightarrow Equation(2)$

• By solving the equations we get v₁ = 30, v₂=10

The velocity of the boat and the river are 30m/s and 10m/s respectively.